A061136 - OEIS

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A061136

Number of degree-n odd permutations of order dividing 4.

0, 0, 1, 3, 12, 40, 120, 336, 2128, 13392, 118800, 850960, 6004416, 38408448, 260321152, 1744135680, 17067141120, 167200393216, 1838196972288, 18345298804992, 181218866222080, 1673804042803200, 16992835499329536

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OFFSET

0,4

LINKS

Table of n, a(n) for n=0..22.

Lev Glebsky, Melany Licón, Luis Manuel Rivera, On the number of even roots of permutations, arXiv:1907.00548 [math.CO], 2019.

FORMULA

E.g.f.: 1/2*exp(x + 1/2*x^2 + 1/4*x^4) - 1/2*exp(x - 1/2*x^2 - 1/4*x^4).

CROSSREFS

Cf. A000085, A001470, A001472, A052501, A053496 - A053505, A001189, A001471, A001473, A061121 - A061128, A000704, A061129 - A061132, A048099, A051695, A061133 - A061135, A001465, A061136 - A061140.

Sequence in context: A327319 A080929 A052482 * A308648 A247002 A027991

Adjacent sequences: A061133 A061134 A061135 * A061137 A061138 A061139

KEYWORD

easy,nonn

AUTHOR

Vladeta Jovovic, Apr 14 2001

STATUS

approved