A347774 E.g.f.: Product_{k>=1} 1 / (1 - x^k)^tan(x).

1, 0, 2, 9, 52, 450, 3410, 41748, 415952, 5985144, 79468648, 1263309960, 20581146056, 375092849040, 7053697259856, 144054799315560, 3108398855786496, 70281839877041088, 1687564595412611520, 42264952015652902656, 1114043035100431983744, 30552235678578565203840

Offset

0,3

Links

Table of n, a(n) for n=0..21.

Formula

E.g.f.: exp( tan(x) * Sum_{k>=1} sigma(k)*x^k/k ).

E.g.f.: exp( tan(x) * Sum_{k>=1} x^k/(k*(1 - x^k)) ).

Prog

(PARI) N=40; x='x+O('x^N); Vec(serlaplace(1/prod(k=1, N, (1-x^k)^tan(x))))
(PARI) N=40; x='x+O('x^N); Vec(serlaplace(exp(tan(x)*sum(k=1, N, sigma(k)*x^k/k))))
(PARI) N=40; x='x+O('x^N); Vec(serlaplace(exp(tan(x)*sum(k=1, N, x^k/(k*(1-x^k))))))

Crossrefs

Cf. A000203, A346547, A346841, A346941.

Sequence in context: A124347 A360743 A360193 * A360718 A266469 A371226

Adjacent sequences: A347771 A347772 A347773 * A347775 A347776 A347777

Keyword

nonn

Author

Seiichi Manyama, Sep 18 2021

Status

approved