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 A174450 #11 Sep 08 2022 08:45:51 %S A174450 1,1,1,1,12,1,1,24,24,1,1,40,960,40,1,1,60,2400,2400,60,1,1,84,5040, %T A174450 201600,5040,84,1,1,112,9408,564480,564480,9408,112,1,1,144,16128, %U A174450 1354752,81285120,1354752,16128,144,1,1,180,25920,2903040,243855360,243855360,2903040,25920,180,1 %N A174450 Triangle T(n, k, q) = n!*(n+1)!*q^k/((n-k)!(n-k+1)!) if floor(n/2) > k-1, otherwise n!*(n+1)!*q^(n-k)/(k!*(k+1)!) for q = 2, read by rows. %H A174450 G. C. Greubel, <a href="/A174450/b174450.txt">Rows n = 0..50 of the triangle, flattened</a> %F A174450 T(n, k, q) = n!*(n+1)!*q^k/((n-k)!(n-k+1)!) if floor(n/2) > k-1, otherwise n!*(n+1)!*q^(n-k)/(k!*(k+1)!) for q = 2. %F A174450 T(n, n-k, q) = T(n, k, q). %F A174450 From _G. C. Greubel_, Nov 29 2021: (Start) %F A174450 T(2*n, n, q) = q^n*(2*n+1)!*Catalan(n) for q = 2. %F A174450 T(n, k, q) = binomial(n, k)*binomial(n+1, k+1) * ( k!*(k+1)!*q^k/(n-k+1) if (floor(n/2) >= k), otherwise ((n-k)!)^2*q^(n-k) ), for q = 2. (End) %e A174450 Triangle begins as: %e A174450 1; %e A174450 1, 1; %e A174450 1, 12, 1; %e A174450 1, 24, 24, 1; %e A174450 1, 40, 960, 40, 1; %e A174450 1, 60, 2400, 2400, 60, 1; %e A174450 1, 84, 5040, 201600, 5040, 84, 1; %e A174450 1, 112, 9408, 564480, 564480, 9408, 112, 1; %e A174450 1, 144, 16128, 1354752, 81285120, 1354752, 16128, 144, 1; %e A174450 1, 180, 25920, 2903040, 243855360, 243855360, 2903040, 25920, 180, 1; %t A174450 T[n_, k_, q_]:= If[Floor[n/2]>k-1, n!*(n+1)!*q^k/((n-k)!*(n-k+1)!), n!*(n+1)!*q^(n-k)/(k!*(k+1)!)]; %t A174450 Table[T[n, k, 2], {n,0,12}, {k,0,n}]//Flatten %o A174450 (Magma) %o A174450 F:= Factorial; // T = A174450 %o A174450 T:= func< n,k,q | Floor(n/2) gt k-1 select F(n)*F(n+1)*q^k/(F(n-k)*F(n-k+1)) else F(n)*F(n+1)*q^(n-k)/(F(k)*F(k+1)) >; %o A174450 [T(n,k,2): k in [0..n], n in [0..12]]; // _G. C. Greubel_, Nov 29 2021 %o A174450 (Sage) %o A174450 f=factorial %o A174450 def A174450(n,k,q): %o A174450 if ((n//2)>k-1): return f(n)*f(n+1)*q^k/(f(n-k)*f(n-k+1)) %o A174450 else: return f(n)*f(n+1)*q^(n-k)/(f(k)*f(k+1)) %o A174450 flatten([[A174450(n,k,2) for k in (0..n)] for n in (0..12)]) # _G. C. Greubel_, Nov 29 2021 %Y A174450 Cf. A174449 (q=1), this sequence (q=2), A174451 (q=3). %Y A174450 Cf. A000108. %K A174450 nonn,tabl,easy %O A174450 0,5 %A A174450 _Roger L. Bagula_, Mar 20 2010 %E A174450 Edited by _G. C. Greubel_, Nov 29 2021