OFFSET
0,3
COMMENTS
a(n) is also the constant term in product 1 <= i,j <= n, i different from j (1 - x_i/x_j)^4. - Sharon Sela (sharonsela(AT)hotmail.com), Feb 16 2002
REFERENCES
George E. Andrews, Richard Askey and Ranjan Roy, Special Functions, Cambridge University Press, 1998.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..130
J.-C. Novelli and J.-Y. Thibon, Hopf Algebras of m-permutations,(m+1)-ary trees, and m-parking functions, arXiv preprint arXiv:1403.5962 [math.CO], 2014-2020.
FORMULA
From Amiram Eldar, Jan 26 2022: (Start)
Sum_{n>=0} 1/a(n) = (cos(2^(3/4)*3^(1/4)) + cosh(2^(3/4)*3^(1/4)))/2.
Sum_{n>=0} (-1)^n/a(n) = cos(6^(1/4))*cosh(6^(1/4)). (End)
MATHEMATICA
Table[(4n)!/24^n, {n, 0, 10}] (* Harvey P. Dale, Oct 15 2015 *)
PROG
(PARI) a(n)=(4*n)!/24^n;
CROSSREFS
KEYWORD
nonn
AUTHOR
BjornE (mdeans(AT)algonet.se)
STATUS
approved