A346925 a(n) = Sum_{d|n} mu(n/d) * binomial(3*d,d) / (2*d+1).

1, 2, 11, 52, 272, 1414, 7751, 43208, 246663, 1430440, 8414639, 50065628, 300830571, 1822758766, 11124755380, 68328711696, 422030545334, 2619630794574, 16332922290299, 102240108466928, 642312451209982, 4048514835624478, 25594403741131679, 162250237951706584

Offset: 1

Author

Ilya Gutkovskiy, Aug 07 2021

Keywords

• nonn

Comments

Moebius transform of A001764.

Crossrefs

Cf. A001764, A002996, A008683.

Programs

Mathematica

Table[Sum[MoebiusMu[n/d] Binomial[3 d, d]/(2 d + 1), {d, Divisors[n]}], {n, 24}]

PARI

a(n) = sumdiv(n, d, moebius(n/d)*binomial(3*d, d)/(2*d+1)); \\ Michel Marcus, Aug 07 2021