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 A387479 #13 Sep 01 2025 03:07:47
%S A387479 1,0,0,2,6,0,4,48,36,8,216,648,232,768,5184,6944,3696,28800,86464,
%T A387479 71712,137376,691328,1185216,1067904,4280512,12749952,15523200,
%U A387479 26248832,102010752,201056256,243856384,694548480,1995570432,3031771136,5109762048,16129681920
%N A387479 a(n) = Sum_{k=0..floor(n/3)} 2^k * 3^(n-3*k) * binomial(k,n-3*k)^2.
%H A387479 Vincenzo Librandi, <a href="/A387479/b387479.txt">Table of n, a(n) for n = 0..2000</a>
%F A387479 G.f.: 1/sqrt((1-2*x^3-6*x^4)^2 - 48*x^7).
%t A387479 Table[Sum[2^k* 3^(n-3*k)*Binomial[k,n-3*k]^2,{k,0,Floor[n/3]}],{n,0,40}] (* _Vincenzo Librandi_, Sep 01 2025 *)
%o A387479 (PARI) a(n) = sum(k=0, n\3, 2^k*3^(n-3*k)*binomial(k, n-3*k)^2);
%o A387479 (Magma) [(&+[2^k *3^(n-3*k)* Binomial(k,n-3*k)^2: k in [0..Floor(n/3)]]): n in [0..40]]; // _Vincenzo Librandi_, Sep 01 2025
%Y A387479 Cf. A108490, A387478.
%K A387479 nonn,new
%O A387479 0,4
%A A387479 _Seiichi Manyama_, Aug 30 2025