Number of fixed-point free involutions in a fixed Sylow 2-subgroup of the symmetric group of degree 2n.
A332840
Number of fixed-point free involutions in a fixed Sylow 2-subgroup of the symmetric group of degree 2n.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =3a(4) =17a(5) =17a(6) =51a(7) =51a(8) =417a(9) =417a(10) =1251a(11) =1251a(12) =7089a(13) =7089a(14) =21267a(15) =21267a(16) =206657a(17) =206657a(18) =619971a(19) =619971a(20) =3513169a(21) =3513169a(22) =10539507a(23) =10539507a(24) =86175969a(25) =86175969a(26) =258527907a(27) =258527907a(28) =1464991473a(29) =1464991473
External references
- oeis: A332840