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

Author

Brian Nakamura, Apr 02 2013

Keywords

• nonn

Links

• 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.

Crossrefs

Cf. A005802, A217057.

Programs

Maple

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