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 A207613 #10 Jan 02 2016 14:04:50 %S A207613 1,2,2,3,4,4,5,8,8,8,8,16,20,16,16,13,30,44,48,32,32,21,56,92,112,112, %T A207613 64,64,34,102,188,256,272,256,128,128,55,184,372,560,672,640,576,256, %U A207613 256,89,328,724,1184,1552,1696,1472,1280,512,512,144,580,1384 %N A207613 Triangle of coefficients of polynomials v(n,x) jointly generated with A207612; see Formula section. %C A207613 Only column 1 contains odd numbers. %C A207613 column 1: A000045 (Fibonacci sequence) %C A207613 row sums: A002878 (bisection of Lucas sequence) %C A207613 top edge: A000079 (powers of 2) %F A207613 u(n,x) = u(n-1,x) + v(n-1,x), v(n,x) = u(n-1,x) + 2x*v(n-1,x) + 1, where u(1,x) = 1, v(1,x) = 1. %F A207613 With offset 0, the Riordan array ((1 + z)/(1 - z - z^2), 2*z*(1 - z)/(1 - z - z^2)) with o.g.f. (1 + z)/(1 - z - z^2 - x*(2*z - 2*z^2)) = 1 + (2 + 2*x)*z + (3 + 4*x + 4*x^2)*z^2 + .... - _Peter Bala_, Dec 30 2015 %e A207613 First five rows: %e A207613 1 %e A207613 2 2 %e A207613 3 4 4 %e A207613 5 8 8 8 %e A207613 8 16 20 16 16 %t A207613 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A207613 u[n_, x_] := u[n - 1, x] + v[n - 1, x] %t A207613 v[n_, x_] := u[n - 1, x] + 2 x*v[n - 1, x] + 1 %t A207613 Table[Factor[u[n, x]], {n, 1, z}] %t A207613 Table[Factor[v[n, x]], {n, 1, z}] %t A207613 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A207613 TableForm[cu] %t A207613 Flatten[%] (* A207612 *) %t A207613 Table[Expand[v[n, x]], {n, 1, z}] %t A207613 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A207613 TableForm[cv] %t A207613 Flatten[%] (* A207613 *) %Y A207613 A000045 (column 1), A000079 (main diagonal), A002878 (row sums). Cf. A207612, A208510. %K A207613 nonn,tabl,easy %O A207613 1,2 %A A207613 _Clark Kimberling_, Feb 19 2012