GAMES

A triskaidekaphobic may fearthe number 13, but we have reason to celebrate

How many pennies do you need to make a stack as tall or taller than a penny set
on its edge? Most people will say nine or ten, but you must actually use 13
pennies.

We started thinking about the number 13 last February when we got a letter from
Monte Zerger, a mathematician at Adams State College in Alamosa, Colorado. "The
thirteenth anniversary of Omni in 1991 will be particularly auspicious because
ninety-one is the sum of the numbers one through thirteen," wrote Zerger, who
along with Dan Shine of Cincinnati served as our numerological consultant this
month. Zerger also pointed out that the alphabet's middle letters-M (the
thirteenth letter from the beginning of the alphabet) and N (the thirteenth
letter from the end of the alphabet)-are also the middle letters in the name
Omni-enclosed by the middle vowels. Omni's logo even contains a hidden portent:
Rearrange the four shapes to read no. 13.

Mathematically, 13 is a fascinating number. The first "teen" number, it is both
a prime number (the sixth, after 2, 3, 5, 7, and 11) and a Fibonacci number, in
which each number of the series is the sum of the previous two. (13 is the
seventh, after 1, 1, 2, 3, 5, and 8.) The number 13 is also the first "emirp," a
prime number that turns into a different prime number when reversed (31).

Elsewhere in mathematics, Euclid's Elements are contained in 13 books. There
are 13 Archimedean polyhedrons. And a cube has 13 axes of symmetry: Three go
through opposite faces, four through diagonally opposite vertices, and six
through opposite edges.

Other 13-related facts include 13 cards in a suit (hearts, diamonds, spades, and
clubs) in every standard deck of playing cards. In music, an octave consists of
13 notes.

But while the recipient of a baker's dozen is certainly fortunate, is it wise to
celebrate when you're 13 years old? We're not superstitious, but just to be safe
consider this anniversary issue of Omni the start of our fourteenth year.

The number 13, some people believe, seems to have almost supernatural
powers. And those who suffer from triskaidekaphobia, the fear of the number 13,
won't reserve a seat in the thirteenth row of an airplane, eat at a table
seating 13 people, or rent a room on the thirteenth floor (although few, if any,
hotels and office buildings officially have a thirteenth floor),

The superstition about 13 people at a dinner table supposedly harks back to the
Last Supper, as told in the Gospel according to Saint John. Jesus Christ and his
12 apostles gathered for the last time before he was arrested and eventually
executed. When Judas, the apostle who betrayed Christ, left, the thirteenth
chair remained empty.

While the number 13 has been associated with Judas and the Last Supper, it also
makes an unlucky appearance in other cultures. In Norse mythology, for example,
12 gods were invited to a dinner party. The god of mischief, Loki, crashed the
party, and during the affair one of the guests was killed.

There's certainly no doubt that the number 13 has its dark side. There are
traditionally 13 witches in a coven, 13 steps on a gallows, and 13 coils of rope
in a hangman's noose. And the thirteenth card of the tarot deck represents
death, reminiscent of the Black Death, the plague that swept across Europe in
the 1300's.

Superstition also can affect history. During the late Fifties, the Colombiana,
a group of Italian experts on the life of Christopher Columbus, reviewed all the
documents related to the explorer's historic arrival in the Americas. They
concluded that Columbus actually landed in the New World on October 13, 1492.
The man entrusted with Christopher Columbus's log and papers may have
deliberately changed the date to October 12 to avoid the evil omen of the number
13.

But 13 has not always been considered evil or unlucky. The ancient Egyptians
considered death, the thirteenth stage of earthly life, as the transition to
eternal life. For them, death was a transformation, not an ending. And unlike
the Last Supper, the thirteenth chair at King Arthur's Round Table was a seat of
honor, reserved for the knight who would find the Holy Grail.

The number is also significant in American history. The 13 original colonies
are represented everywhere, from the 13 red and white stripes on the flag to the
13 steps on the pyramid in the Great Seal, which appears on the back of a dollar
bill.

THIRTEEN QUIZ

The following questions relate to the number 13.

1. In addition to the steps of the pyramid, the number 13 is represented in many
ways on a dollar bill, some of them intentional, others not. How many can you
find?

2. What 13-sided polygon occurs in the natural world?

3. What is the most abundant metallic element in the earth's crust?

4. What 13-member group exports petroleum?

5. What is the difference between the Julian and the Gregorian calendars?

6. What heroine was proud of her 13-inch waist?

7.In what fictional tale do 13 dwarfs take a collective journey?

8. Why is it ironic that Friday the thirteenth is considered unlucky?

9. The first permanent English settlement in the New World was established on
May 13, 1607. What significant event occurred 132 years later? And 132 years
after that?

10. What novel begins, "It was a bright cold day in April and the clocks were
striking thirteen"?

11. What unlucky moon mission exploded in 1970?

12. What is significant about 132 and 312?

13. What composer, born in 1813, composed 13 operas and has 13 letters in his
name

ANSWERS

1. There are 13 letters in the motto ANNUIT COEPTIS above the pyramid; 13 stars
above the eagle's head; 13 stripes on its shield; and 13 letters in the motto E
PLURIBUS UNUM, on the ribbon in its beak. The eagle also holds 13 war arrows on
one side and a peace branch with 13 olives and 13 leaves on the other side.
There are 13 beads in the decorative "rattlesnake tail" chains on the outer
sides of the Great Seal. And the date, in Roman numerals, 1776, is printed
directly opposite 1789, the only other date on every dollar bill-in the green
Treasury seal next to Washington's portrait. The difference between the two
dates is 13 years.

2. Viewed from outside the solar system, Earth's moon travels around the sun,
tracing a path that resembles a 13-sided polygon with rounded corners.

3. The thirteenth element, aluminum.

4. 13 member nations make up OPEC, the Organization of Petroleum Exporting
Countries.

5. The Julian calendar currently lags 13 days behind the Gregorian calendar and
will remain so until the year 2100. Then the difference will become 14 days.

6. Scarlett O'Hara in Gone With the Wind.

7. In The Hobbit, by J.R.R. Tolkien, 13 dwarfs escort Bilbo Baggins from the
Shire to the Lonely Mountains.

8. The thirteenth of the month is more likely to fall on a Friday than on any
other day of the week. Our calendar repeats itself, exactly, every 400 years.
During each 400-year period, the thirteenth of the month occurs on Friday 688
times.

9. 1607 + 169 = 1776, the year of the American Revolution. 1776 + 169 1945, the
year World War 11 ended, the year the first atomic bomb was dropped, and the
year Franklin Delano Roosevelt died, 13 years after he was first elected
President of the United States.

10. George Orwell's 1984.

11. Apollo 13.

12. 132 = 169; 312 = 961, the reverse of 169.

13. Richard Wagner.