A284718 Number of indecomposable permutations avoiding the pattern 1324.

1, 1, 1, 3, 13, 69, 396, 2355, 14363, 89706, 573828, 3758866, 25195016, 172591294, 1206482317, 8592827996, 62257890162, 458214977642, 3421294482237, 25884913987768, 198236423171483, 1535315006313002, 12015208271571543, 94943908405295171, 757044806198966152

Offset

0,4

Links

Bjarki Ágúst Guðmundsson, Table of n, a(n) for n = 0..50 (terms 25..50 by Bjarki Ágúst Guðmundsson, computed using Kotesovec's formula and terms from the Conway/Guttmann/Zinn-Justin reference)

Andrew R. Conway, Anthony J. Guttmann and Paul Zinn-Justin, 1324-avoiding permutations revisited, arXiv preprint arXiv:1709.01248 [math.CO], 2017.

A. L. L. Gao, S. Kitaev, P. B. Zhang. On pattern avoiding indecomposable permutations, arXiv:1605.05490 [math.CO], 2016.

Formula

For n>1, a(n) = A061552(n) + 3*A000108(n) - A000108(n+1) - 2*A000108(n-1). - Vaclav Kotesovec, Apr 02 2017

Crossrefs

Cf. A061552.

Sequence in context: A121954 A058307 A020107 * A284719 A128079 A074534

Adjacent sequences: A284715 A284716 A284717 * A284719 A284720 A284721

Keyword

nonn

Author

N. J. A. Sloane, Apr 02 2017

Extensions

More terms from Vaclav Kotesovec, Apr 02 2017

a(0) prepended by Bjarki Ágúst Guðmundsson, Dec 18 2017

Status

approved