A220873 Number of enhanced set partitions of n elements treatable by "PTR" (Procedure Triple Reverse).

1, 2, 5, 15, 44, 147, 439, 1484, 4469, 15217

Offset

1,2

Links

Table of n, a(n) for n=1..10.

Lily Yen, A Bijection for Crossings and Nestings, arXiv preprint arXiv:1209.3082, 2012

Crossrefs

Sequence in context: A292524 A071742 A035355 * A148351 A148352 A151463

Adjacent sequences: A220870 A220871 A220872 * A220874 A220875 A220876

Keyword

nonn

Author

N. J. A. Sloane, Dec 27 2012

Status

approved