OFFSET
1,1
COMMENTS
Row n has Catalan(n) terms.
The rows converge to A076050.
LINKS
Rémy Sigrist, Rows n = 1..10 of triangle, flattened
D. Kremer, Permutations with forbidden subsequences and a generalized Schröder number, Discrete Math. 218 (2000) 121-130.
Julian West, Generating trees and the Catalan and Schröder numbers, Discrete Math. 146 (1995), 247-262.
Julian West, Generating trees and forbidden subsequences, Discrete Math., 157 (1996), 363-374.
EXAMPLE
The triangle starts with a root node (at level 1) labeled 2; thereafter every node labeled k has k children at the next level whose labels are 2, 3, 4, ..., k, k+1.
Rows 1, 2, 3, 4, 5, and part of 6 are:
2,
2, 3,
2, 3, 2, 3, 4,
2, 3, 2, 3, 4, 2, 3, 2, 3, 4, 2, 3, 4, 5,
2, 3, 2, 3, 4, 2, 3, 2, 3, 4, 2, 3, 4, 5, 2, 3, 2, 3, 4, 2, 3, 2, 3, 4, 2, 3, 4, 5, 2, 3, 2, 3, 4, 2, 3, 4, 5, 2, 3, 4, 5, 6,
2, 3, 2, 3, 4, 2, 3, 2, 3, 4, 2, 3, 4, 5, 2, 3, 2, 3, 4, 2, 3, 2, 3, 4, 2, 3, 4, 5, 2, 3, 2, 3, 4, 2, 3, 4, 5, 2, 3, 4, 5, 6, ...
...
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
N. J. A. Sloane, Nov 29 2017
STATUS
approved