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 A368047 #11 Dec 10 2023 17:24:10
%S A368047 0,1,9,10,50,35,147,84,324,165,605,286,1014,455,1575,680,2312,969,
%T A368047 3249,1330,4410,1771,5819,2300,7500,2925,9477,3654,11774,4495,14415,
%U A368047 5456,17424,6545,20825,7770,24642,9139,28899,10660,33620,12341
%N A368047 a(n) = (-1)^n * n*(n + 1)*(2*n + (-1)^n * (4*n + 5) + 1) / 12.
%H A368047 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (0,4,0,-6,0,4,0,-1).
%F A368047 a(n) = Sum_{n=0..k} (-1)^(n-k) *A368045(n, k).
%F A368047 G.f.: x*(1 + 9*x + 6*x^2 + 14*x^3 + x^4 + x^5)/((1 - x)^4*(1 + x)^4). - _Stefano Spezia_, Dec 10 2023
%t A368047 A368047[n_]:=n(n+1)(2n+(-1)^n(4n+5)+1)(-1)^n/12;Array[A368047,50,0] (* or *)
%t A368047 LinearRecurrence[{0,4,0,-6,0,4,0,-1},{0,1,9,10,50,35,147,84},50] (* _Paolo Xausa_, Dec 10 2023 *)
%Y A368047 Cf. A368045, A368046.
%K A368047 nonn,easy
%O A368047 0,3
%A A368047 _Peter Luschny_, Dec 09 2023