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 A172311 #19 Jan 24 2022 08:02:49 %S A172311 0,1,2,4,6,8,12,14,14,18,18,20,24,24,38,34,42,34,26,28,32,38,52,54,64, %T A172311 58,68,60,60,50,66,70,70,74,50,52,60,54,64,66,84,88,116,106,132,100, %U A172311 136,126,140,106,118,100,122,106,138,114,138,132,152,156,176,158,190,166,158,154,98,88,132,82,124,94,112 %N A172311 First differences of A172310. %C A172311 Number of L-toothpicks added to the L-toothpick structure of A172310 at the n-th stage. %H A172311 David Applegate, <a href="/A139250/a139250.anim.html">The movie version</a> %H A172311 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 A172311 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> %Y A172311 Cf. A139250, A139251, A160121, A160171, A160173, A161207, A161329, A172310. %K A172311 nonn %O A172311 0,3 %A A172311 _Omar E. Pol_, Jan 31 2010 %E A172311 More terms from _Nathaniel Johnston_, Nov 15 2010 %E A172311 Corrected by _David Applegate_ and _Omar E. Pol_; more terms beyond a(22) from _David Applegate_, Mar 26 2016