A242310 - OEIS

%I #12 May 16 2014 16:01:56

%S 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,

%T 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,

%U 6,4,8,2,11,2,2,4,4,2,8,4,2,2,11,4,4,4

%N 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.

%C k is the number of divisors of arithmetic numbers A003601.

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

%Y Cf. A000203, A003601, A049642.

%K nonn

%O 1,3

%A _Ilya Lopatin_ and _Juri-Stepan Gerasimov_, May 10 2014