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 A154593 #6 May 08 2025 22:55:47 %S A154593 1,-1,3,9,6,9,-73,-75,9,27,849,1644,774,108,81,-12241,-33849,-28098, %T A154593 -6426,243,243,211929,763314,938007,442044,60183,1458,729,-4280473, %U A154593 -18995271,-31035393,-22471479,-6681123,-528525,3645,2187,98806689,521068632,1064559708,1049509224,501783174,99717480,4802652,17496,6561 %N A154593 A triangle of polynomial coefficients:{a, b, c, d} = {2, 3, 3, 2}; p(x,n)=(-1)^(n)*(1 - d - c x)^(n + 1)*Sum[(a*k + b)^n*(c*x + d)^k, {k, 0, Infinity}]. %C A154593 Row sums are: {1, 2, 24, -112, 3456, -80128, 2417664, -83986432, 3340271616, -149428830208, 7427651272704,...} %C A154593 This result is from a scan of {a,b,c,d} that are quadratic symmetric. %F A154593 {a, b, c, d} = {2, 3, 3, 2}; %F A154593 p(x,n)=(-1)^(n)*(1 - d - c x)^(n + 1)*Sum[(a*k + b)^n*(c*x + d)^k, {k, 0, Infinity}]; %F A154593 t(n,m)=coefficients(p(x,n)). %F A154593 p(x,n)=(-2)^n *(-1 - 3 x)^(1 + n)* LerchPhi[2 + 3 x, -n, 3/2] %e A154593 Triangle begins: %e A154593 {1}, %e A154593 {-1, 3}, %e A154593 {9, 6, 9}, %e A154593 {-73, -75, 9, 27}, %e A154593 {849, 1644, 774, 108, 81}, %e A154593 {-12241, -33849, -28098, -6426, 243, 243}, %e A154593 {211929, 763314, 938007, 442044, 60183, 1458, 729}, %e A154593 {-4280473, -18995271, -31035393, -22471479, -6681123, -528525, 3645, 2187}, %e A154593 {98806689, 521068632, 1064559708, 1049509224, 501783174, 99717480, 4802652, 17496, 6561}, %e A154593 ... %t A154593 Clear[p, a, b, c, d, n]; %t A154593 {a, b, c, d} = {2, 3, 3, 2}; %t A154593 p[x_, n_] = (-1)^(n)*(1 - d - c x)^(n + 1)*Sum[(a*k + b)^n*(c*x + d)^k, {k, 0, Infinity}]; %t A154593 Table[FullSimplify[ExpandAll[p[x, n]]], {n, 0, 10}]; %t A154593 Table[CoefficientList[FullSimplify[ExpandAll[p[x, n]]], x], {n, 0, 10}]; %t A154593 Flatten[%] %K A154593 uned,tabl,sign %O A154593 0,3 %A A154593 _Roger L. Bagula_, Jan 12 2009