Number of permutations in S_n avoiding {bar 4}2153 (i.e., every occurrence of 2153 is contained in an occurrence of a 42153).

A137536

Number of permutations in S_n avoiding {bar 4}2153 (i.e., every occurrence of 2153 is contained in an occurrence of a 42153).

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =23a(5) =104a(6) =532a(7) =3002a(8) =18375a(9) =120559a(10) =840480a(11) =6184729a(12) =47788384a(13) =386126534a(14) =3251434927a(15) =28454039404

External references