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A153788 Number of proper divisors of the Catalan number A000108(n). 1
0, 0, 1, 1, 3, 7, 11, 7, 15, 15, 23, 31, 47, 71, 191, 95, 191, 255, 575, 511, 767, 767, 1023, 1151, 1151, 1727, 1535, 1535, 4095, 4095, 5119, 2047, 6143, 12287, 12287, 8191, 12287, 12287, 24575, 24575, 36863, 98303, 131071, 147455 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

FORMULA

a(n) = A032741(A000108(n)) = A152763(n) - 1.

MATHEMATICA

DivisorSigma[0, CatalanNumber@Range[0, 1000]] - 1 (* G. C. Greubel, Aug 28 2016 *)

PROG

(PARI) a(n)=numdiv(binomial(2*n, n)/(n+1)) - 1 \\ Charles R Greathouse IV, Aug 29 2016

CROSSREFS

Cf. A000108, A032741, A152762, A152763, A152988.

Sequence in context: A125254 A093931 A335980 * A167486 A260408 A261103

Adjacent sequences:  A153785 A153786 A153787 * A153789 A153790 A153791

KEYWORD

nonn

AUTHOR

Omar E. Pol, Jan 18 2009

STATUS

approved

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Last modified January 16 03:28 EST 2021. Contains 340195 sequences. (Running on oeis4.)