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Possible values for sum of perfect divisors of n.
4

%I #2 Mar 30 2012 19:00:23

%S 1,2,3,5,6,7,10,11,12,13,14,15,17,18,19,20,21,22,23,24,26,28,29,30,31,

%T 33,34,35,37,38,39,40,41,42,43,44,45,46,47,48,50,51,52,53,54,55,56,57,

%U 58,59,60,61,62,63,65,66,67,68,69,70,71,72,73,74,75

%N Possible values for sum of perfect divisors of n.

%C Perfect divisor of n is divisor d such that d^k = n for some k >= 1. See A175067 (sum of perfect divisors of n) and A175081 (values taken by the sum of perfect divisors of n (A175067) sorted into ascending order).

%C Complement of A001597(n+1) for n >= 1 (perfect powers >= 4). a(n) = A007916(n-1) for n >= 2. [From _Jaroslav Krizek_, Jan 30 2010]

%K nonn

%O 1,2

%A _Jaroslav Krizek_, Jan 24 2010