|
%I #14 May 27 2018 19:46:09
%S 1,-1,1,-5,20,-104,584,-4304,35720,-329160,3239112,-36135912,
%T 438454752,-5743527360,80351263680,-1218698312064,19599583392384,
%U -334335747652224,6019295318075520,-114911886106373760,2305234779285164544,-48596575400453366784
%N E.g.f.: Product_{k>=1} 1/(1 + x^k/k).
%H Seiichi Manyama, <a href="/A292358/b292358.txt">Table of n, a(n) for n = 0..449</a>
%F a(n) ~ (-1)^n * n!. - _Vaclav Kotesovec_, Sep 15 2017
%F E.g.f.: exp(Sum_{k>=1} Sum_{j>=1} (-1)^k*x^(j*k)/(k*j^k)). - _Ilya Gutkovskiy_, May 27 2018
%t nmax = 20; CoefficientList[Series[Product[1/(1 + x^k/k), {k, 1, nmax}], {x, 0, nmax}], x] * Range[0, nmax]! (* _Vaclav Kotesovec_, Sep 15 2017 *)
%o (PARI) {a(n) = n!*polcoeff(1/prod(k=1, n, 1+x^k/k+x*O(x^n)), n)}
%Y Cf. A007838, A007841.
%K sign
%O 0,4
%A _Seiichi Manyama_, Sep 14 2017
|
