A097322 (2n)! divided by denominator of Taylor expansion of exp(cos(x)-1).

1, 4, 1, 1, 4, 1, 1, 4, 1, 11, 4, 1, 1, 4, 11, 1, 4, 31, 1, 44, 29, 1, 4, 1, 11, 4, 29, 1, 4, 11, 1, 4, 31, 1, 1276, 1, 41, 4, 1, 11, 116, 1, 1, 292, 11, 1, 4, 31, 127571, 44, 1, 1, 4, 1, 319, 4, 41, 1, 4, 11, 1, 4, 899, 1, 44, 1, 1, 4, 29, 11, 4, 1, 1, 4, 583, 1, 4756, 361429

Offset: 1

Author

Ralf Stephan, Aug 08 2004

Keywords

• nonn
• easy

Crossrefs

Equals A010050(n) / A047690(n).

Cf. A005046.

Programs

PARI

a(n)=(2*n)!/denominator(polcoeff(Ser(exp(cos(x)-1)),2*n))