OFFSET
1,2
REFERENCES
J. P. Delahaye and P. Mathieu, La bataille, enfin analysee, in Pour la Science, pp. 101 No. 215 September 1995 Paris.
FORMULA
a(n) = {(4n)!/(4!)^n + (2n)!/(2!)^n}/2.
PROG
(PARI) a(n) = ((4*n)!/24^n + (2*n)!/2^n)/2 \\ Charles R Greathouse IV, Sep 06 2016
CROSSREFS
KEYWORD
fini,full,nonn,easy
AUTHOR
Lekraj Beedassy, Sep 03 2005
STATUS
approved