A346941 - OEIS

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A346941

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

1, 1, 4, 15, 90, 555, 4815, 41034, 443268, 4977381, 64274655, 857332366, 13328296014, 207666642131, 3620701556017, 65845797790798, 1294049887432888, 26168756518235801, 576107273399556987, 12940593913711504118, 311924384689270232770, 7752903433736003497447, 203126367130952306670541

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

OFFSET

0,3

LINKS

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

FORMULA

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

E.g.f.: exp( cos(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)^cos(x))))

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

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