cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A300188 a(n) = n! * [x^n] Product_{k>=1} 1/(1 + x^k)^(n/k).

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%I A300188 #9 Sep 08 2018 06:05:27
%S A300188 1,-1,4,-39,536,-9115,185904,-4461877,123647488,-3886461081,
%T A300188 136538590400,-5300491027711,225313697972736,-10409021924850211,
%U A300188 519298241645107456,-27824560148201248125,1593597443825288904704,-97153909607626767338353,6281720886474120790582272
%N A300188 a(n) = n! * [x^n] Product_{k>=1} 1/(1 + x^k)^(n/k).
%H A300188 Vaclav Kotesovec, <a href="/A300188/b300188.txt">Table of n, a(n) for n = 0..300</a>
%F A300188 a(n) = n! * [x^n] exp(-n*Sum_{k>=1} A048272(k)*x^k/k).
%F A300188 a(n) ~ (-1)^n * c * d^n * n^n, where d = 1.3587950730244927060955... and c = 0.6449711831436950784... - _Vaclav Kotesovec_, Sep 08 2018
%e A300188 The table of coefficients of x^k in expansion of e.g.f. Product_{k>=1} 1/(1 + x^k)^(n/k) begins:
%e A300188 n = 0: (1),  0,   0,     0,     0,       0,        0,  ...
%e A300188 n = 1:  1, (-1),  1,    -5,    23,    -119,      619,  ...
%e A300188 n = 2:  1,  -2,  (4),  -16,    92,    -568,     3856,  ...
%e A300188 n = 3:  1,  -3,   9,  (-39),  243,   -1737,    13671,  ...
%e A300188 n = 4:  1,  -4,  16,   -80,  (536),  -4256,    37504,  ...
%e A300188 n = 5:  1,  -5,  25,  -145,  1055,  (-9115),   88075,  ...
%e A300188 n = 6:  1,  -6,  36,  -240,  1908,  -17784,  (185904), ...
%t A300188 Table[n! SeriesCoefficient[Product[1/(1 + x^k)^(n/k), {k, 1, n}], {x, 0, n}], {n, 0, 18}]
%Y A300188 Cf. A048272, A281266, A294356, A299033, A299034, A300187.
%K A300188 sign
%O A300188 0,3
%A A300188 _Ilya Gutkovskiy_, Feb 28 2018