A061133 Number of degree-n even permutations of order exactly 6.

0, 0, 0, 0, 0, 0, 210, 5040, 37800, 201600, 2044350, 25530120, 213993780, 1692490800, 19767998250, 232823791200, 2235629476080, 23171222430720, 294649445112750, 4300403589581400, 55176842335916700, 660577269463243440

Offset: 1

Author

Vladeta Jovovic, Apr 14 2001

Keywords

• easy
• nonn

Crossrefs

Cf. A000085, A001470, A001472, A052501, A053496 - A053505, A001189, A001471, A001473, A061121 - A061128, A000704, A061129 - A061132, A048099, A051695, A061133 - A061135.

Formula

E.g.f.: exp(x) - 1/2*exp(x + 1/2*x^2) - 1/2*exp(x - 1/2*x^2) - exp(x + 1/3*x^3) + 1/2*exp(x + 1/2*x^2 + 1/3*x^3 + 1/6*x^6) + 1/2*exp(x - 1/2*x^2 + 1/3*x^3 - 1/6*x^6).