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 A373654 #8 Jun 12 2024 17:22:09
%S A373654 1,1,1,1,3,5,7,12,21,34,55,92,153,251,414,686,1133,1869,3088,5103,
%T A373654 8427,13917,22990,37975,62721,103598,171121,282646,466852,771119,
%U A373654 1273690,2103796,3474913,5739647,9480387,15659094,25864698,42721676,70564951,116554700,192517665
%N A373654 a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-5*k-1,k).
%H A373654 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,2,0,0,-1).
%F A373654 G.f.: 1 / (1 - x/(1 - x^3)^2).
%F A373654 a(n) = a(n-1) + 2*a(n-3) - a(n-6) for n > 6.
%o A373654 (PARI) a(n) = sum(k=0, n\3, binomial(2*n-5*k-1, k));
%Y A373654 Cf. A373639.
%K A373654 nonn,easy
%O A373654 0,5
%A A373654 _Seiichi Manyama_, Jun 12 2024