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 A176200 #12 Sep 08 2022 08:45:52 %S A176200 1,1,1,1,7,1,1,21,21,1,1,51,131,51,1,1,113,603,603,113,1,1,239,2381, %T A176200 4831,2381,239,1,1,493,8585,31237,31237,8585,493,1,1,1003,29215, %U A176200 176467,312379,176467,29215,1003,1,1,2025,95679,910383,2620707,2620707,910383,95679,2025,1 %N A176200 A symmetrical triangle T(n, m) = 2*Eulerian(n+1, m) -1, read by rows. %C A176200 Row sums are: {1, 2, 9, 44, 235, 1434, 10073, 80632, 725751, 7257590, 79833589, ...}. %H A176200 G. C. Greubel, <a href="/A176200/b176200.txt">Rows n = 0..100 of triangle, flattened</a> %F A176200 T(n, m) = 2*Eulerian(n+1, m) - 1, where Eulerian(n, k) = A008292(n,k). %e A176200 Triangle begins as: %e A176200 1; %e A176200 1, 1; %e A176200 1, 7, 1; %e A176200 1, 21, 21, 1; %e A176200 1, 51, 131, 51, 1; %e A176200 1, 113, 603, 603, 113, 1; %e A176200 1, 239, 2381, 4831, 2381, 239, 1; %e A176200 1, 493, 8585, 31237, 31237, 8585, 493, 1; %t A176200 Eulerian[n_, k_]:= Sum[(-1)^j*Binomial[n+1, j]*(k-j+1)^n, {j,0,k+1}]; %t A176200 T[n_, m_]:= 2*Eulerian[n+1, m]-1; %t A176200 Table[T[n, m], {n,0,12}, {m,0,n}]//Flatten (* modified by _G. C. Greubel_, Apr 25 2019 *) %o A176200 (PARI) Eulerian(n,k) = sum(j=0,k+1, (-1)^j*binomial(n+1,j)*(k-j+1)^n); {T(n,k) = 2*Eulerian(n+1,k) - 1 }; %o A176200 for(n=0,10, for(k=0,n, print1(T(n,k), ", "))) \\ _G. C. Greubel_, Apr 25 2019 %o A176200 (Magma) Eulerian:= func< n,k | (&+[(-1)^j*Binomial(n+1,j)*(k-j+1)^n: j in [0..k+1]]) >; %o A176200 [[2*Eulerian(n+1,k)-1: k in [0..n]]: n in [0..12]]; // _G. C. Greubel_, Apr 25 2019 %o A176200 (Sage) %o A176200 def Eulerian(n,k): return sum((-1)^j*binomial(n+1,j)*(k-j+1)^n for j in (0..k+1)) %o A176200 def T(n,k): return 2*Eulerian(n+1,k)-1 %o A176200 [[T(n,k) for k in (0..n)] for n in (0..12)] # _G. C. Greubel_, Apr 25 2019 %Y A176200 Cf. A008292, A109128. %K A176200 nonn,tabl %O A176200 0,5 %A A176200 _Roger L. Bagula_, Apr 11 2010 %E A176200 Edited by _G. C. Greubel_, Apr 25 2019