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numbers!

Sweet!

The mathematician's numerology: What's special about this number? (link from b_v_borgia)

A few gems:
93 = 333 in base 5.
111 is the smallest possible magic constant of a 3 x 3 magic square of distinct primes.
145 = 1! + 4! + 5!
197 is a Keith number.
226 is the first number he doesn't have anything for.
384 = 8!!
666 is a palindromic triangular number.
668 is the number of legal pawn moves in chess.

Comments

meerkat299
Mar. 8th, 2005 02:37 am (UTC)
Re: curious
according to
http://mathworld.wolfram.com/DoubleFactorial.html

8!! ≠ (8!)! as I was originally assuming.

for positive, even integers, it is
n!! = n×(n-2)×(n-4)×...×6×4×2

for positive, odd integers, it is
n!! = n×(n-2)×(n-4)×...×5×3×1

Thus 8!! = 8×6×4×2 = 384

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