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.
%I A273198 #15 Mar 08 2020 11:36:31
%S A273198 1,-2,296,-327984,1363872384,-15198541159680,372495898187043840,
%T A273198 -17616182020373076940800,1464370216956293433318604800,
%U A273198 -199499758936277018742988067635200,42181903584776412718275835664105472000,-13251216132203374725100642797337549799424000
%N A273198 a(n) = T(n,2) with T(n, m) = (m*n+1)! * Sum_{k=0..n}( 1/(m*k+1) * Sum_{j=0..m*k} (-1)^j*C(k,j)*j^(m*n) ).
%H A273198 G. C. Greubel, <a href="/A273198/b273198.txt">Table of n, a(n) for n = 0..123</a>
%F A273198 a(n) ~ (-1)^n * sqrt(Pi) * 2^(4*n) * n^(4*n + 1/2) / (sqrt(1-c) * exp(4*n) * c^n * (2-c)^(n-1)), where c = -LambertW(-2*exp(-2)) = -A226775 = 0.4063757399599599... . - _Vaclav Kotesovec_, Jun 26 2016
%t A273198 Flatten[{1, Table[(2*n + 1)! * Sum[1/(2*k + 1)*Sum[(-1)^j*Binomial[k, j]*j^(2*n), {j, 0, 2*k}], {k, 0, n}], {n, 1, 10}]}] (* _Vaclav Kotesovec_, Jun 26 2016 *)
%o A273198 (Sage)
%o A273198 def T(n, m): return factorial(m*n+1) * sum(1/(m*k+1)*sum((-1)^j*binomial(k,j)* j^(m*n) for j in (0..m*k)) for k in (0..n))
%o A273198 def a(n): return T(n, 2)
%o A273198 print([a(n) for n in (0..12)])
%Y A273198 Cf. A129814, A273196, A273197.
%K A273198 sign
%O A273198 0,2
%A A273198 _Peter Luschny_, Jun 26 2016