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 A168113 #13 Feb 24 2021 02:48:18 %S A168113 1,1,2,3,3,3,6,7,6,3,6,7,8,9,16,17,10,3,6,7,8,9,16,17,12,9,16,19,22, %T A168113 31,46,41,18,3,6,7,8,9,16,17,12,9,16,19,22,31,46,41,20,9,16,19,22,31, %U A168113 46,43,30,31,48 %N A168113 First differences of A168112. %C A168113 a(n) is the number of toothpicks added at the n-th round in the toothpick structure of A168112. %H A168113 David Applegate, Omar E. Pol and N. J. A. Sloane, <a href="/A000695/a000695_1.pdf">The Toothpick Sequence and Other Sequences from Cellular Automata</a>, Congressus Numerantium, Vol. 206 (2010), 157-191. [There is a typo in Theorem 6: (13) should read u(n) = 4.3^(wt(n-1)-1) for n >= 2.] %H A168113 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> %F A168113 Observation: It appears that a(2^i+2) = 3, for i>0. %F A168113 a(n) = A160731(n)/2. [From _Nathaniel Johnston_, Mar 28 2011] %e A168113 If written as a triangle, begins: %e A168113 1; %e A168113 1; %e A168113 2; %e A168113 3,3; %e A168113 3,6,7,6; %e A168113 3,6,7,8,9,16,17,10; %e A168113 3,6,7,8,9,16,17,12,9,16,19,22,31,46,41,18; %e A168113 Rows converge to A168114. %Y A168113 Cf. A139250, A139251, A152978, A152980, A160407, A168112, A168114. %K A168113 nonn,tabf %O A168113 1,3 %A A168113 _Omar E. Pol_, Dec 07 2009 %E A168113 Terms after a(34) from _Nathaniel Johnston_, Mar 28 2011