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A066803 a(n) = gcd(2^n + 1, 3^n + 1). 2
1, 5, 1, 1, 1, 5, 1, 1, 19, 25, 1, 1, 1, 145, 1, 1, 1, 5, 1, 1, 43, 5, 1, 97, 1, 265, 19, 1, 1, 25, 1, 1, 67, 5, 1, 1, 1, 5, 1, 1, 1, 145, 1, 1, 19, 5, 1, 1, 1, 12625, 307, 1, 1, 5, 1, 1, 1, 5, 1, 241, 1, 5, 817, 1, 1, 5, 1, 1, 139, 725, 1, 55969, 1, 745, 1, 1, 1, 265, 1, 1, 3097, 5, 499 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) divides a(k*n) if k is odd. - Robert Israel, Nov 15 2015

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = gcd(A000051(n), A034472(n)). - Michel Marcus, Nov 15 2015

MAPLE

seq(igcd(2^n+1, 3^n+1), n=1..100); # Robert Israel, Nov 15 2015

MATHEMATICA

Table[GCD[3^n+1, 2^n+1], {n, 90}] (* Harvey P. Dale, Dec 03 2012 *)

PROG

(PARI) { for (n=1, 1000, write("b066803.txt", n, " ", gcd(3^n + 1, 2^n + 1)) ) } \\ Harry J. Smith, Mar 28 2010

CROSSREFS

Cf. A000051 (2^n+1), A034472 (3^n+1).

Sequence in context: A109768 A069293 A293235 * A089608 A250131 A100615

Adjacent sequences:  A066800 A066801 A066802 * A066804 A066805 A066806

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Jan 18 2002

STATUS

approved

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Last modified May 21 18:56 EDT 2019. Contains 323444 sequences. (Running on oeis4.)