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 A129460 #13 Feb 08 2024 08:45:50 %S A129460 1,10,156,3696,125280,5780160,349090560,26760222720,2540101939200, %T A129460 292579402752000,40213832085504000,6502800338141184000, %U A129460 1222285449585328128000,264279998869470904320000 %N A129460 Third column (m=2) of triangle A129065. %C A129460 See A129065 for the M. Bruschi et al. reference. %H A129460 G. C. Greubel, <a href="/A129460/b129460.txt">Table of n, a(n) for n = 0..250</a> %F A129460 a(n) = A129065(n+2, 2), n >= 0. %t A129460 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 A129460 A129460[n_]:= T[n+2,2]; %t A129460 Table[A129460[n], {n,0,40}] (* _G. C. Greubel_, Feb 08 2024 *) %o A129460 (Magma) %o A129460 function T(n,k) // T = A129065 %o A129460 if k lt 0 or k gt n then return 0; %o A129460 elif n eq 0 then return 1; %o A129460 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 A129460 end if; %o A129460 end function; %o A129460 A129460:= func< n | T(n+2, 2) >; %o A129460 [A129460(n): n in [0..20]]; // _G. C. Greubel_, Feb 08 2024 %o A129460 (SageMath) %o A129460 @CachedFunction %o A129460 def T(n,k): # T = A129065 %o A129460 if (k<0 or k>n): return 0 %o A129460 elif (n==0): return 1 %o A129460 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 A129460 def A129460(n): return T(n+2,2) %o A129460 [A129460(n) for n in range(41)] # _G. C. Greubel_, Feb 08 2024 %Y A129460 Cf. A129065, A129459 (m=1), A129461 (m=3). %K A129460 nonn,easy %O A129460 0,2 %A A129460 _Wolfdieter Lang_, May 04 2007