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 A387482 #13 Aug 31 2025 15:26:47
%S A387482 1,0,0,3,6,0,9,72,36,27,486,972,297,2592,11664,10611,13446,97200,
%T A387482 195129,149688,663876,2334987,2838726,4697676,21485817,43705008,
%U A387482 51438240,171480483,517850982,760446144,1440329769,5065354440,10479570372,15691149819,44973017478
%N A387482 a(n) = Sum_{k=0..floor(n/3)} 3^k * 2^(n-3*k) * binomial(k,n-3*k)^2.
%H A387482 Vincenzo Librandi, <a href="/A387482/b387482.txt">Table of n, a(n) for n = 0..2000</a>
%F A387482 G.f.: 1/sqrt((1-3*x^3-6*x^4)^2 - 72*x^7).
%t A387482 Table[Sum[3^k* 2^(n-3*k)*Binomial[k,n-3*k]^2,{k,0,Floor[n/3]}],{n,0,40}] (* _Vincenzo Librandi_, Aug 31 2025 *)
%o A387482 (PARI) a(n) = sum(k=0, n\3, 3^k*2^(n-3*k)*binomial(k, n-3*k)^2);
%o A387482 (Magma) [(&+[3^k * 2^(n-3*k) * Binomial(k,n-3*k)^2: k in [0..Floor(n/3)]]): n in [0..40]]; // _Vincenzo Librandi_, Aug 31 2025
%Y A387482 Cf. A387480, A387481.
%K A387482 nonn,new
%O A387482 0,4
%A A387482 _Seiichi Manyama_, Aug 30 2025