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 A113284 #5 Oct 18 2020 07:03:45
%S A113284 1,5,23,113,579,3047,16319,88489,484255,2668951,14793169,82372723,
%T A113284 460436551,2582033519,14519686915,81845419777,462319557311,
%U A113284 2616334071987,14830559353869,84189874112659,478559722392493
%N A113284 Odd bisection of A113281: a(n) = A113281(2*n+1).
%F A113284 G.f.: ( (1+x)/(1-x)/(1-6*x+x^2)*(1-x-(1-6*x+x^2)^(1/2))/2/x )^(1/2).
%F A113284 a(n) ~ (1 + sqrt(2))^(2*n + 3/2) / (2*sqrt(Pi*n)). - _Vaclav Kotesovec_, Oct 18 2020
%o A113284 (PARI) {a(n)=local(x=X+X*O(X^n));polcoeff( (2*(1+x)/(1-x)/(1-6*x+x^2)/(1-x+(1-6*x+x^2)^(1/2)) )^(1/2),n,X)}
%Y A113284 Cf. A113281, A113282, A113283.
%K A113284 nonn
%O A113284 0,2
%A A113284 _Paul D. Hanna_, Oct 22 2005