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 A274704 #15 Jan 05 2020 05:34:17
%S A274704 1,-5,621,-437593,1026405753,-6054175060941,75477454065058725,
%T A274704 -1766732850877953050849,71248914440011028226682737,
%U A274704 -4637564239713542128355021380117,462852368857623061805761137170608989,-67965094887205237792816627191801312013545
%N A274704 Exponential generating function 1/M_{4}(z^4) where M_{n}(z) is the n-th Mittag-Leffler function, nonzero coefficients only.
%H A274704 Robert Israel, <a href="/A274704/b274704.txt">Table of n, a(n) for n = 0..128</a>
%F A274704 E.g.f. (nonzero coefficients): 2*z/(cosh(z)+cos(z)).
%F A274704 For n >= 1, a(n) = - Sum_{k=0..n-1} a(k)*binomial(4*k+1,4*n+1). - _Robert Israel_, Jul 04 2016
%p A274704 s := series(2*z/(cosh(z)+cos(z)),z,60):
%p A274704 seq((4*n+1)!*coeff(s,z,4*n+1),n=0..11);
%t A274704 c = CoefficientList[Series[1/MittagLefflerE[4, z^4], {z, 0, 15*4}], z];
%t A274704 Table[Factorial[4*n+1]*c[[4*n+1]], {n, 0, 12}]
%Y A274704 Cf. A181983 (n=1), A009843 (n=2), A274703 (n=3), A274705 (array).
%K A274704 sign
%O A274704 0,2
%A A274704 _Peter Luschny_, Jul 03 2016