OFFSET
0,2
COMMENTS
Central terms of the triangle A247500.
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 0..250
G.-N. Han and H. Xiong, Difference operators for partitions and some applications, arXiv preprint arXiv:1508.00772 [math.CO], 2015-2018.
FORMULA
a(n) = A248045(n+1) / (n+1).
MATHEMATICA
Table[((2n)!(2n+1)!)/((n+1)^2 n!^3), {n, 0, 20}] (* Harvey P. Dale, May 17 2019 *)
PROG
(Haskell)
a204515 n = a247500 (2 * n) n
(PARI) a(n) = (2*n)! * (2*n+1)! / ((n+1)^2 * n!^3); \\ Michel Marcus, Feb 03 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Oct 19 2014
STATUS
approved