A224249 Number of permutations in S_n containing exactly 2 increasing subsequences of length 4.

0, 0, 0, 0, 4, 63, 665, 5982, 49748, 396642, 3089010, 23745117, 181282899, 1379847138, 10496697584, 79928658289, 609847716251, 4665446254886, 35801131210504, 275638351332190, 2129514056354378, 16509890253429971, 128449405928666831, 1002835093225654416, 7856166360951643384

Offset

1,5

Links

Table of n, a(n) for n=1..25.

Andrew R. Conway and Anthony J. Guttmann, Counting occurrences of patterns in permutations, arXiv:2306.12682 [math.CO], 2023. See pp. 16, 24, 25.

B. Nakamura and D. Zeilberger, Using Noonan-Zeilberger Functional Equations to enumerate (in Polynomial Time!) Generalized Wilf classes

B. Nakamura and D. Zeilberger, Using Noonan-Zeilberger Functional Equations to enumerate (in Polynomial Time!) Generalized Wilf classes, Adv. in Appl. Math. 50 (2013), 356-366.

Maple

# programs can be obtained from the Nakamura and Zeilberger link.

Crossrefs

Cf. A005802, A217057.

Sequence in context: A102197 A094323 A286438 * A361140 A335112 A227619

Adjacent sequences: A224246 A224247 A224248 * A224250 A224251 A224252

Keyword

nonn

Author

Brian Nakamura, Apr 02 2013

Status

approved