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A129224
Residues of the Lucas - Lehmer primality test for M(23) = 8388607.
8
4, 14, 194, 37634, 7031978, 7033660, 1176429, 7643358, 3179743, 2694768, 763525, 4182158, 7004001, 1531454, 5888805, 1140622, 4321431, 7041324, 2756392, 1280050, 6563009, 6107895
OFFSET
0,1
COMMENTS
Since a(21) > 0, M(23) = 8388607 is composite. Mersenne numbers are only prime if a(p-2) = 0.
LINKS
Eric Weisstein's World of Mathematics, Lucas Lehmer Test.
FORMULA
a(0) = 4, a(n) = a(n-1)^2 mod 2^p-1. Last term: a(p-2).
EXAMPLE
a(21) = 6563009^2 - 2 mod 8388607 = 6107895.
KEYWORD
fini,full,nonn
AUTHOR
Sergio Pimentel, Apr 04 2007
STATUS
approved