A087968 a(n) = gcd(1 + 2^n, n^2).

1, 1, 9, 1, 1, 1, 1, 1, 27, 25, 1, 1, 1, 1, 9, 1, 1, 1, 1, 1, 9, 1, 1, 1, 1, 1, 81, 1, 1, 25, 1, 1, 9, 1, 1, 1, 1, 1, 9, 1, 1, 1, 1, 1, 27, 1, 1, 1, 1, 125, 9, 1, 1, 1, 121, 1, 9, 1, 1, 1, 1, 1, 27, 1, 1, 1, 1, 289, 9, 25, 1, 1, 1, 1, 9, 1, 1, 169, 1, 1, 243, 1, 1, 1, 1, 1, 9, 1, 1, 25, 1, 1, 9, 1, 1, 1

Offset

1,3

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Example

a(9) = gcd(2^9 + 1,9^2) = gcd(513,81) = 27.

Maple

seq(gcd(2^n+1, n^2), n=1..100); # Muniru A Asiru, Sep 22 2018

Prog

(PARI) A087968(n) = gcd((2^n)+1, n^2); \\ Antti Karttunen, Sep 22 2018
(GAP) List([1..100], n->Gcd(2^n+1, n^2)); # Muniru A Asiru, Sep 22 2018

Crossrefs

Cf. A087966, A087969.

Sequence in context: A284099 A176410 A087966 * A340365 A110483 A348734

Adjacent sequences: A087965 A087966 A087967 * A087969 A087970 A087971

Keyword

nonn

Author

Labos Elemer, Sep 22 2003

Status

approved