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 A129461 #11 Feb 08 2024 08:46:04 %S A129461 1,28,908,37896,2036592,138517632,11692594944,1202885199360, %T A129461 148407122764800,21652192199577600,3690199478509977600, %U A129461 726862474705593139200,163918208008013340672000 %N A129461 Fourth column (m=3) of triangle A129065. %C A129461 See A129065 for the M. Bruschi et al. reference. %H A129461 G. C. Greubel, <a href="/A129461/b129461.txt">Table of n, a(n) for n = 0..245</a> %F A129461 a(n) = A129065(n+3, 3), n >= 0. %t A129461 T[n_, k_]:= T[n, k]= If[k<0 || k>n, 0, If[n==0, 1, 2*(n-1)^2*T[n-1,k] - 4*Binomial[n-1,2]^2*T[n-2,k] +T[n-1,k-1] ]]; (* T=A129065 *) %t A129461 A129461[n_]:= T[n+3,3]; %t A129461 Table[A129461[n], {n,0,40}] (* _G. C. Greubel_, Feb 08 2024 *) %o A129461 (Magma) %o A129461 function T(n,k) // T = A129065 %o A129461 if k lt 0 or k gt n then return 0; %o A129461 elif n eq 0 then return 1; %o A129461 else return 2*(n-1)^2*T(n-1,k) - 4*Binomial(n-1,2)^2*T(n-2,k) + T(n-1,k-1); %o A129461 end if; %o A129461 end function; %o A129461 A129461:= func< n | T(n+3, 3) >; %o A129461 [A129461(n): n in [0..20]]; // _G. C. Greubel_, Feb 08 2024 %o A129461 (SageMath) %o A129461 @CachedFunction %o A129461 def T(n,k): # T = A129065 %o A129461 if (k<0 or k>n): return 0 %o A129461 elif (n==0): return 1 %o A129461 else: return 2*(n-1)^2*T(n-1,k) - 4*binomial(n-1,2)^2*T(n-2,k) + T(n-1,k-1) %o A129461 def A129461(n): return T(n+3,3) %o A129461 [A129461(n) for n in range(41)] # _G. C. Greubel_, Feb 08 2024 %Y A129461 Cf. A129065, A129460 (m=2). %K A129461 nonn,easy %O A129461 0,2 %A A129461 _Wolfdieter Lang_, May 04 2007