Number of permutations that are n-3 "block reversals" away from 12...n.

A007974

Number of permutations that are n-3 "block reversals" away from 12...n.

Terms

    a(0) =1a(1) =6a(2) =52a(3) =389a(4) =2539a(5) =16604a(6) =105365a(7) =654030a(8) =3900116a(9) =22073230a(10) =116855950a(11) =567965207

External references