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 A301465 #7 Mar 24 2018 10:41:28
%S A301465 1,2,7,32,180,1142,8162,63807,541202,4926969,47799429,491254999,
%T A301465 5322191407,60533874755,720300053902,8939841040157,115427887156492,
%U A301465 1546880293065700,21472465304481214,308173758866549496,4565492159926897329,69713352146246150541,1095715822838490323551,17705238547423980566108,293792275476690070452598
%N A301465 G.f.: Sum_{n>=0} ( (1+x)^n + (1+2*x)^n )^n * x^n.
%F A301465 G.f.: Sum_{n>=0} x^n * Sum_{k=0..n} binomial(n,k) * (1+x)^(n*(n-k)) * (1+2*x)^(n*k).
%e A301465 G.f.: A(x) = 1 + 2*x + 7*x^2 + 32*x^3 + 180*x^4 + 1142*x^5 + 8162*x^6 + 63807*x^7 + 541202*x^8 + 4926969*x^9 + 47799429*x^10 + ...
%e A301465 such that
%e A301465 A(x) = 1 + ((1+x) + (1+2*x))*x + ((1+x)^2 + (1+2*x)^2)^2*x^2 + ((1+x)^3 + (1+2*x)^3)^3*x^3 + ((1+x)^4 + (1+2*x)^4)^4*x^4 + ((1+x)^5 + (1+2*x)^5)^5*x^5 + ...
%o A301465 (PARI) {a(n) = my(A=1); A = sum(k=0, n, ((1+x)^k + (1+2*x)^k +x*O(x^n))^k * x^k ); polcoeff(A, n)}
%o A301465 for(n=0, 30, print1(a(n), ", "))
%Y A301465 Cf. A301306, A301312, A301308.
%K A301465 nonn
%O A301465 0,2
%A A301465 _Paul D. Hanna_, Mar 24 2018