A338436 a(n) = n! * [x^n] Product_{k=1..n, gcd(n,k) = 1} 1 / (1 - x^k/k!).

1, 1, 2, 9, 28, 245, 726, 11480, 48560, 735705, 4352050, 98329550, 483122388, 15543026746, 105478954140, 2717386363515, 25322712724800, 896697825211141, 6457456535543802, 307183340680888754, 2920059397230745400, 107461248960479482740, 1360407935621917573380

Offset: 0

Author

Ilya Gutkovskiy, Oct 27 2020

Keywords

• nonn

Crossrefs

Cf. A005651, A057562, A338438.

Programs

Mathematica

Table[n! SeriesCoefficient[Product[1/(1 - Boole[GCD[n, k] == 1] x^k/k!), {k, 1, n}], {x, 0, n}], {n, 0, 22}]