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A321057 a(n) = [x^n] Product_{k>=1} ((1 + x^k)/(1 - x^k))^sigma_n(k). 2
1, 2, 12, 94, 1522, 48154, 3087600, 377880794, 93356591804, 46415548879976, 44773963087975388, 86770399797767582434, 340765670578000502365102, 2625605734866823121935402410, 40755373130582885082115865730892, 1290109927277547765958474680645604818 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Seiichi Manyama, Table of n, a(n) for n = 0..80

MATHEMATICA

Table[SeriesCoefficient[Product[((1 + x^k)/(1 - x^k))^DivisorSigma[n, k], {k, 1, n}], {x, 0, n}], {n, 0, 15}] (* Vaclav Kotesovec, Oct 27 2018 *)

PROG

(PARI) {a(n) = polcoeff(prod(k=1, n, ((1+x^k+x*O(x^n))/(1-x^k+x*O(x^n)))^sigma(k, n)), n)}

CROSSREFS

Cf. A301554, A301555, A301556, A319647, A321042, A321068.

Sequence in context: A304979 A003123 A316143 * A247075 A239837 A239838

Adjacent sequences:  A321054 A321055 A321056 * A321058 A321059 A321060

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Oct 26 2018

STATUS

approved

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Last modified May 17 09:20 EDT 2022. Contains 353741 sequences. (Running on oeis4.)