Number of permutations p of [n] avoiding consecutive odd sums i+p(i), (i+1)+p(i+1) for all i in [n-1].
A285672
Number of permutations p of [n] avoiding consecutive odd sums i+p(i), (i+1)+p(i+1) for all i in [n-1].
Terms
- a(0) =1a(1) =1a(2) =1a(3) =2a(4) =8a(5) =36a(6) =180a(7) =1008a(8) =6336a(9) =46080a(10) =374400a(11) =3369600a(12) =32659200a(13) =344736000a(14) =3886444800a(15) =47348582400a(16) =611264102400
External references
- oeis: A285672