A242310 Largest 1 < k <= A000005(n) such that the sum of k distinct divisors of n is equal to k*m for some m, or 1 if no such k exists.

1, 1, 2, 2, 2, 4, 2, 2, 2, 2, 2, 5, 2, 2, 4, 3, 2, 5, 2, 6, 4, 4, 2, 7, 2, 2, 4, 5, 2, 8, 2, 4, 4, 3, 4, 8, 2, 4, 4, 7, 2, 8, 2, 6, 6, 4, 2, 11, 3, 4, 4, 5, 2, 8, 4, 8, 4, 2, 2, 12, 2, 4, 5, 6, 4, 8, 2, 6, 4, 8, 2, 11, 2, 2, 4, 4, 2, 8, 4, 2, 2, 11, 4, 4, 4

Offset: 1

Author

Ilya Lopatin and Juri-Stepan Gerasimov, May 10 2014

Keywords

• nonn

Comments

k is the number of divisors of arithmetic numbers A003601.

Examples

			a(12) = 5 because 1 + 2 + 4 + 6 + 12 = 25 = 5*5 for m = 5.
		

Crossrefs

Cf. A000203, A003601, A049642.