Number of permutations in S_n avoiding 1{bar 5}234 (i.e., every occurrence of 1234 is contained in an occurrence of a 15234).

A137541

Number of permutations in S_n avoiding 1{bar 5}234 (i.e., every occurrence of 1234 is contained in an occurrence of a 15234).

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =23a(5) =104a(6) =533a(7) =3027a(8) =18769a(9) =125687a(10) =901366a(11) =6876307a(12) =55498146a(13) =471743013a(14) =4207097145a(15) =39237139709

External references