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A066975 a(n) = gcd(binomial(2n,n), 2^n + 1). 1
1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 3, 17, 1, 5, 9, 1, 3, 5, 3, 1, 3, 5, 3, 1, 3, 1, 1, 17, 3, 41, 1, 1, 3, 5, 129, 1, 1, 5, 1, 1, 3, 5, 3, 17, 9, 5, 3, 1, 3, 1, 9, 1, 3, 5, 3, 1, 3, 5, 3, 17, 3, 1, 3, 1, 33, 5, 3, 1, 9, 115825, 3, 97, 3, 5, 99, 1, 129, 5, 3, 1, 1, 5, 3, 17, 11, 5, 3, 1, 3, 35425, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

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

MATHEMATICA

Table[GCD[Binomial[2n, n], 2^n+1], {n, 100}] (* Harvey P. Dale, Aug 26 2012 *)

PROG

(PARI) { for (n=1, 1000, write("b066975.txt", n, " ", gcd(binomial(2*n, n), 2^n + 1)) ) } \\ Harry J. Smith, Apr 12 2010

CROSSREFS

Sequence in context: A088204 A100375 A274613 * A291634 A098877 A225212

Adjacent sequences:  A066972 A066973 A066974 * A066976 A066977 A066978

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Jan 26 2002

STATUS

approved

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Last modified June 17 17:41 EDT 2021. Contains 345085 sequences. (Running on oeis4.)