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 A279306 #6 Dec 12 2016 09:16:37
%S A279306 1,1,13,377,2551,97711,1686481,447824017,2522468131,22174988051,
%T A279306 7129179751261,1852107834946547,34648570480339663,828888380086508653,
%U A279306 273996480127378324681,462007733994120695494433,308514276772559961052721,38471181499444351991058251
%N A279306 Numerators of coefficients in expansion of (cosh(x))/(1 + cos(sqrt(x))).
%H A279306 Clark Kimberling, <a href="/A279306/b279306.txt">Table of n, a(n) for n = 0..1000</a>
%e A279306 (1/2) + (1/8)x + (13/48)x^2 + (377/5760)x^3 + ... ; 1/2, 1/8, 13/48, 377/5760, ... = A279306/A279239.
%t A279306 z = 30; t = CoefficientList[Series[Cosh[x]/(1 + Cos[Sqrt[x]]), {x, 0, z}], x];
%t A279306 Numerator[t] (* A279306 *)
%t A279306 Denominator[t] (* A279239 *)
%Y A279306 Cf. A279239.
%K A279306 nonn,easy,frac
%O A279306 0,3
%A A279306 _Clark Kimberling_, Dec 11 2016