a(n) is the number of permutations p of {1, 2, ..., 2*n} such that for any k in 1..2*n, k and p(k) do not share a common 1-bit.

A351722

a(n) is the number of permutations p of {1, 2, ..., 2*n} such that for any k in 1..2*n, k and p(k) do not share a common 1-bit.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =9a(6) =9a(7) =1a(8) =1a(9) =121a(10) =1089a(11) =729a(12) =729a(13) =1521a(14) =169a(15) =1a(16) =1a(17) =2601a(18) =314721a(19) =1771561a(20) =15944049

External references