The number of bicrucial (with respect to squares) permutations of 1,...,n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =54a(9) =0a(10) =0a(11) =0a(12) =69856a(13) =0a(14) =2930016a(15) =0a(16) =40654860a(17) =0a(18) =162190472a(19) =0a(20) =312348610684a(21) =0a(23) =0