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 A217057 Number of permutations in S_n containing exactly one increasing subsequence of length 4. 5
 0, 0, 0, 0, 1, 12, 102, 770, 5545, 39220, 276144, 1948212, 13817680, 98679990, 710108396, 5150076076, 37641647410, 277202062666, 2056218941678, 15358296210724, 115469557503753, 873561194459596, 6647760790457218, 50871527629923754, 391345137795371013 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,6 LINKS Brian Nakamura and Doron Zeilberger, Table of n, a(n) for n = 0..70 Brian Nakamura and Doron Zeilberger, Using Noonan-Zeilberger Functional Equations to enumerate (in Polynomial Time!) Generalized Wilf classes Brian Nakamura and Doron Zeilberger, Using Noonan-Zeilberger Functional Equations to enumerate (in Polynomial Time!) Generalized Wilf classes, arXiv preprint arXiv:1209.2353, 2012. Wikipedia, Enumerations of specific permutation classes Wikipedia, Subsequence EXAMPLE a(4) = 1: 1234. a(5) = 12: 12453, 12534, 13425, 13452, 14235, 15234, 23145, 23415, 23451, 31245, 41235, 51234. MAPLE # programs can be obtained from the Nakamura & Zeilberger link. CROSSREFS Cf. A005802, A117158, A158005, A214015, A214152. Sequence in context: A261483 A082151 A125375 * A240462 A126533 A052148 Adjacent sequences:  A217054 A217055 A217056 * A217058 A217059 A217060 KEYWORD nonn AUTHOR Alois P. Heinz, Sep 25 2012 STATUS approved

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Last modified December 14 09:41 EST 2019. Contains 329979 sequences. (Running on oeis4.)