OFFSET
0,3
FORMULA
a(0) = 0; a(n) = (2*n-1)*a(n-1) + n.
PROG
(PARI) a001147(n) = prod(k=1, n, 2*k-1);
a(n) = a001147(n)*sum(k=0, n, k/a001147(k));
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Jan 05 2024
STATUS
approved