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A067660 Values of gcd(n!+1,2^n+1) not equal to 1 taking n in increasing order. +0
1
2, 11, 19, 43, 67, 131, 163, 179, 227, 347, 419, 443, 491, 523, 563, 571, 619, 683, 691, 739, 787, 947, 1019, 1051, 1091, 1123, 1187, 1291, 1451, 1499, 1571, 1579, 1667, 1723, 1747, 1867, 1907, 1931, 2003, 2131, 2203, 6043, 2347, 2371, 2531, 2579, 2659 (list; graph; listen)
OFFSET

0,1

FORMULA

If 2m+1 is prime and is in the sequence, 2m+1=gcd(m!+1, 2^m+1)

PROGRAM

(PARI) for(k=0, 3000, d=gcd(k!+1, 2^k+1); if(d<>1, print1(d, ", ")))

CROSSREFS

Sequence in context: A154765 A163997 A067931 this_sequence A103200 A105076 A067670

Adjacent sequences: A067657 A067658 A067659 this_sequence A067661 A067662 A067663

KEYWORD

nonn

AUTHOR

Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 03 2002

EXTENSIONS

Corrected and extended by Rick L. Shepherd (rshepherd2(AT)hotmail.com), May 20 2002

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Last modified November 23 17:09 EST 2009. Contains 167438 sequences.


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