Number of permutations of length n which avoid the patterns 2134, 3214, 4123.

A116805

Number of permutations of length n which avoid the patterns 2134, 3214, 4123.

Terms

    a(0) =1a(1) =2a(2) =6a(3) =21a(4) =74a(5) =256a(6) =876a(7) =2987a(8) =10182a(9) =34726a(10) =118492a(11) =404441a(12) =1380670a(13) =4713644a(14) =16093028a(15) =54944551a(16) =187591798a(17) =640477650a(18) =2186726460a(19) =7465949877a(20) =25490345790a(21) =87029482456a(22) =297137237124

External references