OFFSET
1,2
COMMENTS
Suggested by Eq. (80) of (Maia and Mendez, 2008).
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..452
M. Maia and M. Mendez, On the arithmetic product of combinatorial species, Discr. Math., 308 (2008), 5407-5427.
MAPLE
with(numtheory);
B:=(n, d)->n!/(d!*(n/d)!);
f:=proc(n) local d; global B; option remember;
if n=1 then 1
else add( B(n-1, d)*2^d*f((n-1)/d), d in divisors(n-1)); fi;
end;
[seq(f(n), n=1..40)];
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 09 2017
STATUS
approved