OFFSET
1,2
FORMULA
Observation: lim n -> infinity a(n+2)/a(n) = 4 and it seems that a(n+2)/a(n) < 4 or >4 for infinitely many values of n.
MATHEMATICA
Table[Sum[Binomial[n, Mod[n, k]], {k, n}], {n, 40}] (* Harvey P. Dale, Jul 16 2017 *)
PROG
(PARI) a(n)=sum(k=1, n, binomial(n, n%k))
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Aug 20 2002
STATUS
approved