A284829 Expansion of Sum_{i>=1} mu(i)^2*x^i/(1 - x^i) * Product_{j>=i} 1/(1 - mu(j)^2*x^j), where mu() is the Moebius function (A008683).

1, 3, 5, 9, 13, 23, 30, 45, 64, 89, 118, 165, 211, 282, 369, 475, 606, 779, 978, 1236, 1547, 1922, 2375, 2936, 3602, 4403, 5362, 6506, 7864, 9493, 11399, 13661, 16317, 19443, 23122, 27415, 32418, 38268, 45065, 52968, 62125, 72742, 84969, 99112, 115409, 134139, 155665, 180368, 208658, 241051

Offset: 1

Author

Ilya Gutkovskiy, Apr 03 2017

Keywords

• nonn

Comments

Total number of smallest parts in all partitions of n into squarefree parts (A005117).

Examples

			a(5) = 13 because we have [5], [3, 2], [3, 1, 1], [2, 2, 1], [2, 1, 1, 1], [1, 1, 1, 1, 1] and 1 + 1 + 2 + 1 + 3 + 5 = 13.
		

Links

• Index entries for related partition-counting sequences

Crossrefs

Cf. A005117, A008683, A073576, A092268, A092269, A195820, A281572.

Programs

Mathematica

nmax = 50; Rest[CoefficientList[Series[Sum[MoebiusMu[i]^2 x^i/(1 - x^i) Product[1/(1 - MoebiusMu[j]^2 x^j), {j, i, nmax}], {i, 1, nmax}], {x, 0, nmax}], x]]

PARI

x='x+O('x^50); Vec(sum(i=1, 50, moebius(i)^2*x^i/(1 - x^i) * prod(j=i, 50, 1/(1 - moebius(j)^2*x^j)))) \\ Indranil Ghosh, Apr 04 2017

Formula

G.f.: Sum_{i>=1} mu(i)^2*x^i/(1 - x^i) * Product_{j>=i} 1/(1 - mu(j)^2*x^j).