Number of permutations in S_n avoiding {bar 4}{bar 5}123 (i.e., every occurrence of 123 is contained in an occurrence of a 45123).

A137555

Number of permutations in S_n avoiding {bar 4}{bar 5}123 (i.e., every occurrence of 123 is contained in an occurrence of a 45123).

Terms

    a(0) =1a(1) =1a(2) =2a(3) =5a(4) =14a(5) =43a(6) =147a(7) =578a(8) =2702a(9) =15252a(10) =103150a(11) =817928a(12) =7428844a(13) =75807522a(14) =856512850a(15) =10596715538

External references