A152981 Sum of divisors of Motzkin number A001006(n).

1, 1, 3, 7, 13, 32, 72, 128, 360, 1008, 3836, 9408, 15512, 66960, 252720, 785148, 1137960, 3340800, 13072776, 42465024, 69530400, 238761600, 678562560, 2412043920, 5270534880, 10943277120, 44922182340, 117229255200, 209990825568, 623486730240, 1698651339840, 7019676332760, 18578092462280

Offset

0,3

Links

Amiram Eldar, Table of n, a(n) for n = 0..200

Formula

a(n) = sigma(A001006(n)) = A000203(A001006(n)).

Maple

A152981 := proc(n) numtheory[sigma](A001006(n)) ; end proc:
seq(A152981(n), n=0..40) ; # R. J. Mathar, Jul 08 2011

Mathematica

mot[0] = 1; mot[n_] := mot[n] = mot[n - 1] + Sum[mot[k] * mot[n - 2 - k], {k, 0, n - 2}]; Table[DivisorSigma[1, mot[n]], {n, 0, 32}] (* Amiram Eldar, Nov 26 2019 *)

Crossrefs

Cf. A000005, A000203, A001006, A152761.

Sequence in context: A100382 A292448 A222227 * A112040 A358560 A222187

Adjacent sequences: A152978 A152979 A152980 * A152982 A152983 A152984

Keyword

nonn

Author

Omar E. Pol, Dec 20 2008

Status

approved