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 A155887 #10 Jan 25 2020 01:26:36 %S A155887 1,0,1,0,2,1,0,5,4,1,0,15,14,6,1,0,51,50,27,8,1,0,188,187,113,44,10,1, %T A155887 0,731,730,468,212,65,12,1,0,2950,2949,1956,970,355,90,14,1,0,12235, %U A155887 12234,8291,4356,1785,550,119,16,1,0,51822,51821,35643,19474,8612,3021 %N A155887 Riordan array (1, (1/(1-x))c(x/(1-x))), c(x) the g.f. of A000108. %C A155887 Inverse of (1, x(1-x)/(1+x-x^2)). Row sums are A002212. Augmented version of A104259. %C A155887 Triangle T(n,k) given by [0,F(3)/F(1),F(1)/F(3),F(5)/F(3),F(3)/F(5),F(7)/F(5),F(5)/F(7),...] DELTA [1,0,0,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938, F(n)=A000045(n) (Fibonacci numbers). - _Philippe Deléham_, Jan 31 2009 %F A155887 Riordan array (1, (1-sqrt((1-5x)/(1-x)))/(2x)); %F A155887 G.f.: 1/(1-xy/(1-x-x/(1-x/(1-x-x/(1-x/(1-x-x/(1-... (continued fraction). %e A155887 Triangle begins %e A155887 1; %e A155887 0, 1; %e A155887 0, 2, 1; %e A155887 0, 5, 4, 1; %e A155887 0, 15, 14, 6, 1; %e A155887 0, 51, 50, 27, 8, 1; %e A155887 0, 188, 187, 113, 44, 10, 1; %e A155887 0, 731, 730, 468, 212, 65, 12, 1; %e A155887 0, 2950, 2949, 1956, 970, 355, 90, 14, 1; %e A155887 From _Paul Barry_, Sep 28 2009: (Start) %e A155887 Production matrix is %e A155887 0, 1, %e A155887 0, 2, 1, %e A155887 0, 1, 2, 1, %e A155887 0, 1, 1, 2, 1, %e A155887 0, 1, 1, 1, 2, 1, %e A155887 0, 1, 1, 1, 1, 2, 1, %e A155887 0, 1, 1, 1, 1, 1, 2, 1, %e A155887 0, 1, 1, 1, 1, 1, 1, 2, 1, %e A155887 0, 1, 1, 1, 1, 1, 1, 1, 2, 1 (End) %K A155887 easy,nonn,tabl %O A155887 0,5 %A A155887 _Paul Barry_, Jan 29 2009