a(n) = number of integers in range [2^(n-1),(2^n)-1] which permutation A209861/A209862 sends to even-sized orbits.

A209868

a(n) = number of integers in range [2^(n-1),(2^n)-1] which permutation A209861/A209862 sends to even-sized orbits.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =0a(4) =2a(5) =0a(6) =20a(7) =56a(8) =114a(9) =248a(10) =106a(11) =1016a(12) =1992a(13) =4016a(14) =6506a(15) =7518a(16) =24496a(17) =50358a(18) =121610a(19) =261206a(20) =483160

External references