A350506 -id:A350506 - cp's OEIS frontend

A350505 Irregular triangle read by rows: a(n) is the n-th term of a truncated Kolakoski tree.

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, 184, 185, 55, 56, 84, 126, 16, 17, 136, 311, 12, 13, 20, 48, 32, 33, 113, 51, 392, 78, 52, 79, 119, 405, 80, 81, 277, 278, 414, 621, 82, 83, 283, 125, 425, 191, 2166, 288

Offset: 1

John-Vincent Saddic, Jan 02 2022

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.

			Triangle begins:
  1;
  2, 7;
  3, 4, 15, 24;
  5, 6, 14, 10, 35, 122, 36, 37;
...

Rémy Sigrist, Table of n, a(n) for n = 1..5000
Rémy Sigrist, Illustration of the construction
Rémy Sigrist, C++ program
Index entries for sequences that are permutations of the natural numbers

Inverse is A350506.

Cf. A111081.

cp's OEIS Frontend

A350505 Irregular triangle read by rows: a(n) is the n-th term of a truncated Kolakoski tree.

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