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 A293947 #11 Oct 05 2019 09:16:49 %S A293947 1,3,8,19,41,85,173,349,701,1405,2800,5576,11128,22221,44342,88422, %T A293947 176507,352062,702831,1403235,2802382,5598862,11185734,22353592, %U A293947 44674558 %N A293947 Sequence P(n) arising in the analysis of the Hofstadter "brother" sequence A284644. %H A293947 Altug Alkan, Nathan Fox, and Orhan Ozgur Aybar, <a href="https://doi.org/10.1155/2017/2614163">On Hofstadter Heart Sequences</a>, Complexity, Volume 2017, Article ID 2614163, 8 pages. %Y A293947 Cf. A004001, A005185, A244477, A284644. %K A293947 nonn,more %O A293947 1,2 %A A293947 _N. J. A. Sloane_, Oct 26 2017