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

Author

Omar E. Pol, Dec 20 2008

Keywords

• nonn

Links

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

Crossrefs

Cf. A000005, A000203, A001006, A152761.

Programs

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 *)

Formula

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