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

Author

N. J. A. Sloane, Apr 02 2017

Keywords

• nonn

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.

Crossrefs

Cf. A061552.

Formula

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

Extensions

More terms from Vaclav Kotesovec, Apr 02 2017

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