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 A371779 #8 Apr 06 2024 10:04:18
%S A371779 1,6,45,365,3078,26565,232831,2063235,18435021,165780758,1498533273,
%T A371779 13603087800,123920995101,1132284232215,10372554403620,95233251146671,
%U A371779 876081280823430,8073359613286509,74513645742072841,688682977876117698,6373025238727622277
%N A371779 a(n) = Sum_{k=0..floor(n/3)} binomial(4*n+2,n-3*k).
%F A371779 a(n) = [x^n] 1/(((1-x)^3-x^3) * (1-x)^(3*n)).
%o A371779 (PARI) a(n) = sum(k=0, n\3, binomial(4*n+2, n-3*k));
%Y A371779 Cf. A371777, A371778, A371780.
%Y A371779 Cf. A066381.
%K A371779 nonn
%O A371779 0,2
%A A371779 _Seiichi Manyama_, Apr 05 2024