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 A233971 #13 Jul 15 2024 01:36:54 %S A233971 0,1,2,2,4,2,4,6,8,2,4,6,10,10,8,14,16,2,4,6,10,10,10,18,24,22,8,14, %T A233971 22,26,16,30,32,2,4,6,10,10,10,18,24,22,10,18,28,38,28,46,56,54,8,14, %U A233971 22,26,22,42,56,62,16,30,46,58,32,62,64,2,4,6,10,10 %N A233971 Number of toothpicks added at n-th stage to the structure of A233970. %C A233971 Essentially the first differences of A233970. %C A233971 First differs from A170905 at a(24). %C A233971 First differs from both A233765 and A233781 at a(25). %e A233971 Written as an irregular triangle in which the row lengths is A011782 the sequence (starting from 1) begins: %e A233971 1; %e A233971 2; %e A233971 2,4; %e A233971 2,4,6,8; %e A233971 2,4,6,10,10,8,14,16; %e A233971 2,4,6,10,10,10,18,24,22,8,14,22,26,16,30,32; %e A233971 2,4,6,10,10,10,18,24,22,10,18,28,38,28,46,56,54,8,14,22,26,22,42,56,62,16,30,46,58,32,62,64; %e A233971 Right border gives A000079. %Y A233971 Cf. A000079, A011782, A139251, A161207, A161831, A170905, A182633, A182635, A182841, A233761, A233765, A233781, A233970, A233972. %K A233971 nonn,tabf %O A233971 0,3 %A A233971 _Omar E. Pol_, Dec 18 2013