Number of permutations of [n] that avoid the shuffle pattern s-k-t, where s = 12 and t = 123.

A324135

Number of permutations of [n] that avoid the shuffle pattern s-k-t, where s = 12 and t = 123.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =24a(5) =120a(6) =710a(7) =4815a(8) =36650a(9) =308778a(10) =2850294a(11) =28602468a(12) =310041806a(13) =3610879857a(14) =44975227466a(15) =596677473990

External references