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 A151724 #23 Mar 23 2021 10:41:45 %S A151724 0,1,6,6,18,6,18,30,42,6,18,30,54,54,42,78,90,6,18,30,54,54,54,102, %T A151724 150,102,42,78,138,162,114,186,186,6,18,30,54,54,54,102,150,102,54, %U A151724 102,174,222,198,246,342,198,42,78,138,162,162,258,402,354,162,186 %N A151724 First differences of A151723. %D A151724 S. M. Ulam, On some mathematical problems connected with patterns of growth of figures, pp. 215-224 of R. E. Bellman, ed., Mathematical Problems in the Biological Sciences, Proc. Sympos. Applied Math., Vol. 14, Amer. Math. Soc., 1962 (see Example 6, page 224). %H A151724 N. J. A. Sloane, <a href="/A151724/b151724.txt">Table of n, a(n) for n = 0..4095</a> [First 1024 terms from David Applegate and N. J. A. Sloane] %H A151724 David Applegate, <a href="/A139250/a139250.anim.html">The movie version</a> %H A151724 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 A151724 David Applegate and N. J. A. Sloane, <a href="/A151723/a151723.txt">Table of n, A151724(n), A151723(n) for n = 0..1025</a> %H A151724 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 A151724 N. J. A. Sloane, <a href="https://www.youtube.com/watch?v=9ogbsh8KuEM">Exciting Number Sequences</a> (video of talk), Mar 05 2021. %e A151724 When written as a triangle: %e A151724 0, %e A151724 1, %e A151724 6, %e A151724 6,18, %e A151724 6,18,30,42, %e A151724 6,18,30,54,54,42,78,90, %e A151724 6,18,30,54,54,54,102,150,102,42,78,138,162,114,186,186, %e A151724 ... %e A151724 Right border gives 0 together with A068293. - _Omar E. Pol_, Mar 19 2015 %Y A151724 Cf. A151723, A170898 (after dividing by 6), A170899, A169759. %K A151724 nonn %O A151724 0,3 %A A151724 _David Applegate_ and _N. J. A. Sloane_, Jun 13 2009