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 A194802 #15 Mar 24 2017 00:47:53 %S A194802 0,5,9,23,29,45,57 %N A194802 Number of grid points that are covered after n-th stage of A139250, assuming the vertical toothpicks have length 4 and the horizontal toothpicks have length 2. %C A194802 There are an infinite family of these sequences since A139250 gives the number of toothpicks in the structure regardless of the length difference between horizontal toothpicks and vertical toothpicks. Examples: A147614, A194800, this sequence, A160420, etc. %H A194802 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 A194802 <a href="/index/To#toothpick">Index entries for sequences related to toothpick sequences</a> %e A194802 a(2) = 9. %e A194802 o o o %e A194802 . o . %e A194802 . o . %e A194802 . o . %e A194802 o o o %Y A194802 Cf. A139250, A147614, A162795, A162796, A162797, A175098, A160420, A160422, A194800 %K A194802 nonn,more %O A194802 0,2 %A A194802 _Omar E. Pol_, Sep 07 2011