A338437 - OEIS

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A338437

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

1, 1, 2, 9, 32, 300, 864, 17612, 74752, 1152792, 6470400, 220057992, 719622144, 40754156352, 192835098624, 4787867880000, 55181218873344, 3071730630989952, 11004144881762304, 1179255538492239744, 5720352215040000000, 253837962769406045184, 3262870639485701849088

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

LINKS

Table of n, a(n) for n=0..22.

MATHEMATICA

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

CROSSREFS

Cf. A007841, A057562, A338439.

Sequence in context: A331727 A110376 A335577 * A296151 A036505 A264234

Adjacent sequences: A338434 A338435 A338436 * A338438 A338439 A338440

KEYWORD

nonn

AUTHOR

Ilya Gutkovskiy, Oct 27 2020

STATUS

approved