A246014 Number of permutations of [n] with every alternating run of length less than 3 in which the last alternating run has length 2.

0, 0, 1, 1, 4, 16, 70, 385, 2365, 16337, 125870, 1064810, 9829820, 98319221, 1058927507, 12220050571, 150421002736, 1967299266676, 27243141998506, 398221614894397, 6127294825424317, 98992456408509257, 1675478215412320154, 29646991284088234166

Offset

0,5

Links

Alois P. Heinz, Table of n, a(n) for n = 0..300

Ira M. Gessel, Yan Zhuang, Counting permutations by alternating descents, 2014. See d(n).

Crossrefs

Sequence in context: A280767 A091354 A326654 * A373959 A231373 A161797

Adjacent sequences: A246011 A246012 A246013 * A246015 A246016 A246017

Keyword

nonn

Author

N. J. A. Sloane, Aug 11 2014

Extensions

More terms from Alois P. Heinz, Oct 28 2014

Status

approved