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 A036606 #14 Jul 08 2025 21:48:25 %S A036606 1,1,1,1,1,1,1,1,1,1,1,1,2,3,5,6,8,9,11,11,12,11,11,9,8,6,5,3,2,1,1,1, %T A036606 1,1,2,4,8,14,26,44,76,125,206,327,521,802,1231,1845,2742,3987,5748, %U A036606 8124,11364,15615,21212,28336,37412,48597,62368,78810,98359 %N A036606 Triangle of coefficients of generating function of 4-ary rooted trees of height at most n. %H A036606 E. M. Rains and N. J. A. Sloane, <a href="https://cs.uwaterloo.ca/journals/JIS/cayley.html">On Cayley's Enumeration of Alkanes (or 4-Valent Trees)</a>, J. Integer Sequences, Vol. 2 (1999), Article 99.1.1. %H A036606 <a href="/index/Ro#rooted">Index entries for sequences related to rooted trees</a> %e A036606 Triangle begins: %e A036606 1; %e A036606 1,1; %e A036606 1,1,1,1,1,1; %e A036606 1,1,1,2,3,5,6,8,9,11,11,12,11,11,9,8,6,5,3,2,1,1; %K A036606 nonn,tabf,easy %O A036606 0,13 %A A036606 _N. J. A. Sloane_