4809701440
domain: N
Appears in sequences
- Number of self-inverse permutations on n letters, also known as involutions; number of standard Young tableaux with n cells.at n=19A000085
- Bisection of A000085.at n=9A066224
- Number of involutions in the symmetric group S_n with at least one fixed point.at n=19A378100
- Number of permutations of [n] whose compositional square is the identity permutation or its reverse.at n=19A383835