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 A355909 #14 Sep 19 2022 14:59:12 %S A355909 1,2,3,4,6,9,13,19,28,42,63,94,141,212,318,477,716,1074,1611,2417, %T A355909 3626,5439,8158,12237 %N A355909 Number of nodes at level n in the tree T_0 mentioned in A355905. %C A355909 First differences give A355910. %H A355909 Don Knuth, <a href="http://cs.stanford.edu/~knuth/papers/ambidextrous.pdf">Ambidextrous Numbers</a>, Preprint, September 2022. See (8.1), w_n. %F A355909 a(n) = 1 + (c(n)+c(n-1))/2 where c(n) = |A355908(n)|. %Y A355909 Cf. A355904-A355908, A355910-A355913. %K A355909 nonn,more %O A355909 0,2 %A A355909 _N. J. A. Sloane_, Sep 19 2022