Numbers n that divide the sum of the composite numbers up to n.
1, 2, 3, 4, 9, 47, 604, 1849, 7123, 29588, 71056, 317238, 728941, 945414, 1347895, 3567705, 4624025, 8518502, 77477353
1
T. D. Noe, Plot of 19 terms
No other terms less than 10^9.
Example: 9 is here because 9 divides 4 + 6 + 8 + 9 = 27.
(Mma) s = 0; t = {}; Do[If[! PrimeQ[n], s = s + n]; If[Mod[s, n] == 0, AppendTo[t, n]], {n, 10^6}]; t
Cf. A007506, A009560, A234540, S000054, S000055.
nonn,hard,more
T. D. Noe, May 16 2014