A152762 Sum of proper divisors of Catalan number A000108(n).

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

Offset

0,5

Links

Amiram Eldar, Table of n, a(n) for n = 0..1667

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 A162248 A161755

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