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 A174376 #6 Nov 28 2021 03:29:55 %S A174376 1,1,1,1,4,1,1,6,6,1,1,8,48,8,1,1,10,80,80,10,1,1,12,120,960,120,12,1, %T A174376 1,14,168,1680,1680,168,14,1,1,16,224,2688,26880,2688,224,16,1,1,18, %U A174376 288,4032,48384,48384,4032,288,18,1,1,20,360,5760,80640,967680,80640,5760,360,20,1 %N A174376 Triangle T(n, k) = n!*q^k/(n-k)! if floor(n/2) > k-1 otherwise n!*q^(n-k)/k!, with q = 2, read by rows. %C A174376 Row sums are: {1, 2, 6, 14, 66, 182, 1226, 3726, 32738, 105446, 1141242, ...}. %H A174376 G. C. Greubel, <a href="/A174376/b174376.txt">Rows n = 0..50 of the triangle, flattened</a> %F A174376 T(n, k) = n!*q^k/(n-k)! if floor(n/2) > k-1 otherwise n!*q^(n-k)/k!, with q = 2. %F A174376 T(n, n-k) = T(n, k). %F A174376 T(2*n, n) = A052714(n+1). - _G. C. Greubel_, Nov 28 2021 %e A174376 Triangle begins as: %e A174376 1; %e A174376 1, 1; %e A174376 1, 4, 1; %e A174376 1, 6, 6, 1; %e A174376 1, 8, 48, 8, 1; %e A174376 1, 10, 80, 80, 10, 1; %e A174376 1, 12, 120, 960, 120, 12, 1; %e A174376 1, 14, 168, 1680, 1680, 168, 14, 1; %e A174376 1, 16, 224, 2688, 26880, 2688, 224, 16, 1; %e A174376 1, 18, 288, 4032, 48384, 48384, 4032, 288, 18, 1; %e A174376 1, 20, 360, 5760, 80640, 967680, 80640, 5760, 360, 20, 1; %t A174376 T[n_, k_, q_]:= If[Floor[n/2]>=k, n!*q^k/(n-k)!, n!*q^(n-k)/k!]; %t A174376 Table[T[n, k, 2], {n,0,12}, {k,0,n}]//Flatten %o A174376 (Sage) %o A174376 f=factorial %o A174376 def T(n,k,q): return f(n)*q^k/f(n-k) if ((n//2)>k-1) else f(n)*q^(n-k)/f(k) %o A174376 flatten([[T(n,k,2) for k in (0..n)] for n in (0..12)]) # _G. C. Greubel_, Nov 28 2021 %Y A174376 Cf. A159623 (q=1), this sequence (q=2), A174377 (q=3), A174378 (q=4). %Y A174376 Cf. A052714. %K A174376 nonn,tabl,easy %O A174376 0,5 %A A174376 _Roger L. Bagula_, Mar 17 2010 %E A174376 Edited by _G. C. Greubel_, Nov 28 2021