OFFSET
1,2
LINKS
Ivan Neretin, Table of n, a(n) for n = 1..10000
FORMULA
a(1) = 1, a(2) = 2, for n>=2, a(n+1) = a(n) + sum_{1<=k<n, a(k) divides a(n)} a(k).
MATHEMATICA
a = {1, 2}; Do[AppendTo[a, Plus @@ Intersection[a, Divisors[a[[-1]]]]], {n, 3, 57}]; a (* Ivan Neretin, May 13 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Franklin T. Adams-Watters, Jun 16 2006
STATUS
approved