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 A193860 #9 Jul 16 2013 10:00:27 %S A193860 1,1,5,1,7,19,1,9,33,65,1,11,51,131,211,1,13,73,233,473,665,1,15,99, %T A193860 379,939,1611,2059,1,17,129,577,1697,3489,5281,6305,1,19,163,835,2851, %U A193860 6883,12259,16867,19171,1,21,201,1161,4521,12585,26025,41385,52905 %N A193860 Triangular array: the fission of ((2x+1)^n) by (q(n,x)), where q(n,x)=x^n+x^(n-1)+...+x+1. %C A193860 See A193842 for the definition of fission of two sequences of polynomials or triangular arrays. %F A193860 From _Peter Bala_, Jul 16 2013: (Start) %F A193860 T(n,k) = sum {i = 0..k} binomial(n+1,k-i)*2^(k-i) for 0 <= k <= n. %F A193860 O.g.f.: 1/( (1 - 3*x*t)*(1 - (2*x + 1)*t) ) = 1 + (1 + 5*x)*t + (1 + 7*x + 19*x^2)*t^2 + .... %F A193860 The n-th row polynomial R(n,x) = 1/(1 - x)*( (2*x + 1)^(n+1) - (3*x)^(n+1) ). Cf. A193823. (End) %e A193860 First six rows: %e A193860 1 %e A193860 1...5 %e A193860 1...7....19 %e A193860 1...9....33...65 %e A193860 1...11...51...131...211 %e A193860 1...13...73...233...473...665 %t A193860 z = 10; %t A193860 p[n_, x_] := (2 x + 1)^n; %t A193860 q[0, x_] := 1; q[n_, x_] := x*q[n - 1, x] + 1; %t A193860 p1[n_, k_] := Coefficient[p[n, x], x^k]; %t A193860 p1[n_, 0] := p[n, x] /. x -> 0; %t A193860 d[n_, x_] := Sum[p1[n, k]*q[n - 1 - k, x], {k, 0, n - 1}] %t A193860 h[n_] := CoefficientList[d[n, x], {x}] %t A193860 TableForm[Table[Reverse[h[n]], {n, 0, z}]] %t A193860 Flatten[Table[Reverse[h[n]], {n, -1, z}]] (* A193860 *) %t A193860 TableForm[Table[h[n], {n, 0, z}]] %t A193860 Flatten[Table[h[n], {n, -1, z}]] (* A193861 *) %Y A193860 Cf. A193842, A193861. A193823. %K A193860 nonn,tabl %O A193860 0,3 %A A193860 _Clark Kimberling_, Aug 07 2011