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 A222181 #27 Nov 25 2013 14:56:37 %S A222181 0,1,5,10,10,10,20,30,20,10,20,40,40,30,50,70,40,10,20,40,60,80 %N A222181 Number of pentagons added at n-th stage to the structure of A222180. %C A222181 Essentially the first differences of A222180. %C A222181 Also number of P-toothpicks added at n-th stage to the P-toothpick structure of A222180. %H A222181 N. J. A. Sloane, <a href="/wiki/Catalog_of_Toothpick_and_CA_Sequences_in_OEIS">Catalog of Toothpick and Cellular Automata Sequences in the OEIS</a> %H A222181 <a href="/index/To#toothpick">Index entries for sequences related to toothpick sequences</a> %F A222181 a(n) = 10*A222173(n-2), n >= 3. - _Omar E. Pol_, Nov 24 2013 %e A222181 Apparently this is an irregular triangle: %e A222181 0; %e A222181 1; %e A222181 5; %e A222181 10,10; %e A222181 10,20,30,20; %e A222181 10,20,40,40,30,50,70,40; %e A222181 10,20,40,60,80,... %Y A222181 Cf. A139250, A139251, A147582, A151724, A152968, A161645, A182633, A182841, A222173, A222177, A222180. %K A222181 nonn,tabf,more %O A222181 0,3 %A A222181 _Omar E. Pol_, Mar 15 2013