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 A383355 #24 May 02 2025 04:25:04
%S A383355 1,1,1,1,3,5,7,9,17,31,51,77,129,227,391,641,1067,1829,3157,5351,9033,
%T A383355 15399,26471,45349,77387,132293,227153,390379,670013,1149819,1976595,
%U A383355 3402137,5856157,10079327,17358491,29918957,51590271,88971985,153484661,264898703,457374335
%N A383355 Expansion of 1/sqrt( (1-x) * (1-x-4*x^4) ).
%F A383355 a(n) = Sum_{k=0..floor(n/4)} binomial(2*k,k) * binomial(n-3*k,k).
%o A383355 (PARI) a(n) = sum(k=0, n\4, binomial(2*k, k)*binomial(n-3*k, k));
%Y A383355 Cf. A026569, A217615.
%Y A383355 Cf. A360310.
%K A383355 nonn
%O A383355 0,5
%A A383355 _Seiichi Manyama_, May 01 2025