OFFSET
2,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 2..400
FORMULA
MAPLE
b:= proc(n, k) option remember; `if`(n=0, 1,
add(b(n-j, k)*binomial(n, j), j=k..n))
end:
a:= n-> b(n, 2) -b(n, 3):
seq(a(n), n=2..25);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Aug 04 2014
STATUS
approved