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 A350505 #37 Feb 22 2022 11:49:16 %S A350505 1,2,7,3,4,15,24,5,6,14,10,35,122,36,37,11,61,8,9,21,22,34,23,53,54, %T A350505 184,185,55,56,84,126,16,17,136,311,12,13,20,48,32,33,113,51,392,78, %U A350505 52,79,119,405,80,81,277,278,414,621,82,83,283,125,425,191,2166,288 %N A350505 Irregular triangle read by rows: a(n) is the n-th term of a truncated Kolakoski tree. %C A350505 Construct a tree with these rules: The root node is labeled 1. Children of odd indices are labeled 2. Children of even indices are labeled 1. Nodes labeled 1 have one child. Nodes labeled 2 have two children. At this point, the values of the n-th row comprise the digits in A111081(n). Replace each node labeled 2 with the positive integers in breadth-first order. Remove all nonbranching nodes. %H A350505 Rémy Sigrist, <a href="/A350505/b350505.txt">Table of n, a(n) for n = 1..5000</a> %H A350505 Rémy Sigrist, <a href="/A350505/a350505.png">Illustration of the construction</a> %H A350505 Rémy Sigrist, <a href="/A350505/a350505.txt">C++ program</a> %H A350505 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %e A350505 Triangle begins: %e A350505 1; %e A350505 2, 7; %e A350505 3, 4, 15, 24; %e A350505 5, 6, 14, 10, 35, 122, 36, 37; %e A350505 ... %o A350505 (C++) See Links section. %Y A350505 Inverse is A350506. %Y A350505 Cf. A111081. %K A350505 nonn,look,tabf %O A350505 1,2 %A A350505 _John-Vincent Saddic_, Jan 02 2022