A346580 - OEIS

A346580

a(n) = (1/(6*n)) * Sum_{d|n} mu(n/d) * binomial(6*d,d).

1, 5, 45, 440, 4750, 54081, 642341, 7861216, 98480286, 1256564750, 16273981757, 213378921432, 2826867619108, 37782552518473, 508840821825750, 6898459208449920, 94070535317459017, 1289430373107917718, 17755914760643605781, 245518560759177014000, 3407586451859019939012

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OFFSET

1,2

COMMENTS

Inverse Euler transform of A002295.

Moebius transform of A261499.

LINKS

Table of n, a(n) for n=1..21.

MATHEMATICA

Table[(1/(6 n)) Sum[MoebiusMu[n/d] Binomial[6 d, d], {d, Divisors[n]}], {n, 21}]

PROG

(PARI) a(n) = sumdiv(n, d, moebius(n/d)*binomial(6*d, d))/(6*n); \\ Michel Marcus, Jul 24 2021