A338439 - OEIS

A338439

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

1, 1, 0, 3, 8, 50, 144, 2394, 8448, 89424, 576000, 20124720, 57231360, 3213905760, 11285084160, 217204092000, 2843121254400, 187660890063360, 558255985459200, 64849189355274240, 239933887119360000, 8405611881201561600, 116110668405473280000, 13912098832249673932800

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OFFSET

0,4

LINKS

Table of n, a(n) for n=0..23.

MATHEMATICA

Table[n! SeriesCoefficient[Product[(1 + Boole[GCD[n, k] == 1] x^k/k), {k, 1, n}], {x, 0, n}], {n, 0, 23}]

CROSSREFS

Cf. A007838, A036998, A338437.

Sequence in context: A000862 A306042 A194364 * A005444 A222684 A208801

Adjacent sequences: A338436 A338437 A338438 * A338440 A338441 A338442

KEYWORD

nonn

AUTHOR

Ilya Gutkovskiy, Oct 27 2020

STATUS

approved