A151932 a(n) = 2^(2*n)*(n!)^2*Product_{e_k} binomial(2*e_k, e_k) where 2n = Product p_k^e_k is the prime factorization of 2n.

8, 384, 9216, 2949120, 58982400, 25480396800, 1664719257600, 7457942274048000, 414235422307123200, 165694168922849280000, 26731992586219683840000, 153976277296625378918400000, 10408796345251875614883840000, 24481489004032411446206791680000, 14688893402419446867724075008000000

Offset

1,1

Links

Floris P. van Doorn and Jasper Mulder, Table of n, a(n) for n = 1..250.

Reinhardt Wiewe, Most-perfect magic squares (4)

Example

n = 5: 2n = 10 = 2^1*5^1, a(5) = 2^10*120^2*2*2 = 58982400.

Mathematica

Array[2^(2#) (#!)^2 Times@@(Binomial[2#, # ]&/@FactorInteger[2# ][[All, 2]])&, 12] (* Floris P. van Doorn and Jasper Mulder (florisvandoorn(AT)hotmail.com), Oct 12 2009 *)

Crossrefs

Sequence in context: A326877 A332138 A225698 * A265865 A096205 A162445

Adjacent sequences: A151929 A151930 A151931 * A151933 A151934 A151935

Keyword

nonn,easy

Author

N. J. A. Sloane, Aug 11 2009

Extensions

More terms from Floris P. van Doorn and Jasper Mulder (florisvandoorn(AT)hotmail.com), Oct 12 2009

Status

approved