A300127 Number of Motzkin trees that are "typable closed terms".

0, 1, 2, 3, 10, 34, 98, 339, 1263, 4626, 18099, 73782, 306295, 1319660, 5844714, 26481404, 123172740

Offset

0,3

Comments

From the Bodini-Tarau paper: a Motzkin skeleton is called "typable" if "it exists at least one simply-typed closed lambda term having it as its skeleton".

Links

Table of n, a(n) for n=0..16.

Olivier Bodini, Paul Tarau, On Uniquely Closable and Uniquely Typable Skeletons of Lambda Terms, arXiv:1709.04302 [cs.PL], 2017.

Crossrefs

Cf. A000108, A001006, A135501.

Sequence in context: A358895 A057146 A344573 * A059735 A358213 A356926

Adjacent sequences: A300124 A300125 A300126 * A300128 A300129 A300130

Keyword

nonn,more

Author

Michael De Vlieger, Feb 25 2018

Status

approved