A220872 Number of enhanced partial matchings of n elements treatable by "PTR" (Procedure Triple Reverse).

1, 1, 2, 4, 10, 25, 67, 180, 496, 1370, 3863, 10881, 31448, 90280

Offset

1,3

Links

Table of n, a(n) for n=1..14.

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

Crossrefs

Sequence in context: A268321 A195981 A124500 * A317876 A124501 A124344

Adjacent sequences: A220869 A220870 A220871 * A220873 A220874 A220875

Keyword

nonn

Author

N. J. A. Sloane, Dec 27 2012

Status

approved