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 A299770 #29 Apr 11 2019 22:48:07 %S A299770 1,5,13,21,33,49,65,73,97,105 %N A299770 a(n) is the total number of elements after n-th stage of a hybrid (and finite) cellular automaton on the infinite square grid, formed by toothpicks of length 2, D-toothpicks, toothpicks of length 1, and T-toothpicks. %C A299770 The structure is essentially the same as the finite structure described in A294962 but here there are no D-toothpicks of length sqrt(2)/2. All D-toothpicks in the structure have length sqrt(2). %C A299770 The same as A294962, it seems that this cellular automaton resembles the synthesis of a molecule, a protein, etc. %C A299770 After 10th stage there are no exposed endpoints (or free ends), so the structure is finished. %C A299770 A299771(n) gives the number of elements added to the structure at n-th stage. %C A299770 The "word" of this cellular automaton is "abcd". For further information about the word of cellular automata see A296612. - _Omar E. Pol_, Mar 05 2019 %H A299770 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 A299770 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a> %H A299770 <a href="/index/To#toothpick">Index entries for sequences related to toothpick sequences</a> %Y A299770 Very similar to A294962. %Y A299770 Cf. A299771, A296612. %Y A299770 Cf. A139250 (toothpicks), A160172 (T-toothpicks), A194700 (D-toothpicks), A220500. %Y A299770 For other hybrid cellular automata, see A194270, A220500, A289840, A290220, A294020, A294980. %K A299770 nonn,fini,full %O A299770 1,2 %A A299770 _Omar E. Pol_, Mar 20 2018