OFFSET
0,2
LINKS
Harry J. Smith, Table of n, a(n) for n=0..100
Frank Ellermann, Illustration for A001400, A061924
FORMULA
a(n) = (4*n)! / (4*n-n)!
E.g.f. in Maple notation: hypergeom([1/2, 1/4, 3/4], [1/3, 2/3], 256*x/27). - Karol A. Penson, Oct 18 2001
EXAMPLE
a(13) = 52*51*50*49*48*47*46*45*44*43*42*41*40 (Whist, Bridge).
MATHEMATICA
Table[(4n)!/(4n-n)!, {n, 0, 20}] (* Harvey P. Dale, Aug 20 2012 *)
PROG
(PARI) { for (n=0, 100, write("b061924.txt", n, " ", (4*n)! / (4*n - n)!) ) } \\ Harry J. Smith, Jul 29 2009
(Python)
from sympy import ff
def A061924(n): return ff(n<<2, n) # Chai Wah Wu, Sep 01 2023
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Frank Ellermann, May 16 2001
EXTENSIONS
More terms from Harvey P. Dale, Aug 20 2012
STATUS
approved