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 A129367 #15 Feb 01 2024 01:50:33 %S A129367 36,120,120,300,400,300,630,1000,1000,630,1176,2100,2500,2100,1176, %T A129367 2016,3920,5250,5250,3920,2016,3240,6720,9800,11025,9800,6720,3240, %U A129367 4950,10800,16800,20580,20580,16800,10800,4950,7260,16500,27000,35280,38416,35280,27000,16500,7260 %N A129367 Triangle T(n, k) = A002415(n-k+3)*A002415(k+3), read by rows. %H A129367 G. C. Greubel, <a href="/A129367/b129367.txt">Rows n = 0..50 of the triangle, flattened</a> %F A129367 T(n,k) = A002415(n-k+3)*A002415(k+3), where A002415(n) = n^2*(n^2-1)/12. %F A129367 T(n, n-k) = T(n, k). %e A129367 Triangle begins as: %e A129367 36; %e A129367 120, 120; %e A129367 300, 400, 300; %e A129367 630, 1000, 1000, 630; %e A129367 1176, 2100, 2500, 2100, 1176; %e A129367 2016, 3920, 5250, 5250, 3920, 2016; %e A129367 3240, 6720, 9800, 11025, 9800, 6720, 3240; %e A129367 4950, 10800, 16800, 20580, 20580, 16800, 10800, 4950; %e A129367 7260, 16500, 27000, 35280, 38416, 35280, 27000, 16500, 7260; %t A129367 A129367[n_, k_]:= Binomial[(n-k+3)^2, 2]*Binomial[(k+3)^2, 2]/36; %t A129367 Table[A129367[n,k], {n,0,12}, {k,0,n}]//Flatten %o A129367 (Magma) [Binomial((n-k+3)^2,2)*Binomial((k+3)^2,2)/36: k in [0..n], n in [0..12]]; // _G. C. Greubel_, Jan 31 2024 %o A129367 (SageMath) %o A129367 def A129367(n,k): return binomial((n-k+3)^2,2)*binomial((k+3)^2,2)/36 %o A129367 flatten([[A129367(n,k) for k in range(n+1)] for n in range(13)]) # _G. C. Greubel_, Jan 31 2024 %Y A129367 Cf. A002415, A117662. %K A129367 nonn,tabl,easy,less %O A129367 0,1 %A A129367 _Roger L. Bagula_ and _Gary W. Adamson_, Aug 25 2008 %E A129367 Edited by _G. C. Greubel_, Jan 31 2024