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A152762 Sum of proper divisors of Catalan number A000108(n). 6
0, 0, 1, 1, 10, 54, 204, 243, 1594, 4210, 18484, 62174, 275828, 1131980, 7434360, 10522755, 72469530, 268486410, 1442238420, 4284331050, 18146556060, 62021100660, 248289237960, 798007353390, 2832660378756, 11922780597588 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Table of n, a(n) for n=0..25.

FORMULA

a(n) = A001065(A000108(n)).

a(n) = sigma(binomial(2n,n)/(n+1)) - binomial(2n,n)/(n+1), where sigma(m) is the sum of the divisors of m. - Emeric Deutsch, Dec 24 2008

EXAMPLE

a(4)=10 because the proper divisors of A000108(4)=14 are 1,2 and 7. - Emeric Deutsch, Dec 24 2008

MAPLE

with(numtheory): seq(sigma(binomial(2*n, n)/(n+1))-binomial(2*n, n)/(n+1), n = 0 .. 27); # Emeric Deutsch, Dec 24 2008

MATHEMATICA

DivisorSigma[1, #]-#&/@CatalanNumber[Range[0, 30]] (* Harvey P. Dale, Dec 05 2015 *)

CROSSREFS

Cf. A000108, A000203, A001065, A152761, A152763.

Sequence in context: A208616 A219169 A292058 * A161458 A161755 A053347

Adjacent sequences:  A152759 A152760 A152761 * A152763 A152764 A152765

KEYWORD

easy,nonn

AUTHOR

Omar E. Pol, Dec 14 2008

EXTENSIONS

Extended by Emeric Deutsch, Dec 24 2008

STATUS

approved

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Last modified October 18 22:26 EDT 2019. Contains 328211 sequences. (Running on oeis4.)