Number of permutations of order n avoiding the consecutive pattern 11'22'.

A177470

Number of permutations of order n avoiding the consecutive pattern 11'22'.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =18a(5) =70a(6) =300a(7) =1435a(8) =7910a(9) =47376a(10) =316008a(11) =2314158a(12) =18331236a(13) =158024724a(14) =1462752720a(15) =14497475850a(16) =153488070450

External references