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A066787
a(n) = gcd(2^n + 1, n^2 + 1).
1
1, 5, 1, 17, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 65, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 41, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 29, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 565, 1, 1, 1
OFFSET
1,2
COMMENTS
a(n)=1 or a(n)=0 mod(5) or a(n) is a prime congruent to 1 mod(4).
LINKS
MAPLE
A066787:=n->gcd(2^n+1, n^2+1): seq(A066787(n), n=1..100); # Wesley Ivan Hurt, Jan 03 2016
MATHEMATICA
Table[GCD[2^n + 1, n^2 + 1], {n, 100}] (* Wesley Ivan Hurt, Jan 03 2016 *)
PROG
(PARI) { for (n=1, 1000, write("b066787.txt", n, " ", gcd( 2^n + 1, n^2 + 1)) ) } \\ Harry J. Smith, Mar 25 2010
(Magma) [GCD(2^n+1, n^2+1) : n in [1..100]]; // Wesley Ivan Hurt, Jan 03 2016
CROSSREFS
Sequence in context: A211808 A093826 A144699 * A058352 A376020 A121755
KEYWORD
nonn,easy
AUTHOR
Benoit Cloitre, Jan 18 2002
STATUS
approved