OFFSET
0,2
LINKS
Daniel Suteu, Table of n, a(n) for n = 0..29
MATHEMATICA
Table[Product[(2 k - 1)!!, {k, n + 1}] Sum[(j!/(2 j + 1)!!), {j, 0, n}], {n, 0, 10}] (* Michael De Vlieger, Dec 22 2016 *)
PROG
(PARI) a(n) = prod(k=0, n, prod(i=0, k, 2*i+1))*sum(k=0, n, k!/prod(i=0, k, 2*i+1));
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Daniel Suteu, Dec 21 2016
STATUS
approved