A272978 - OEIS

%I #24 Jul 14 2016 00:19:14

%S 1,2,3,4,5,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,

%T 27,29,30,31,32,33,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,

%U 52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80

%N Numbers not in the range of the sum of perfect divisors function.

%C Numbers which do not appear in A185351 or A187794; that is, there is no integer N whose sum of perfect divisors is equal to a(n) for any n.

%Y Cf. A000396, subsequence of A132999, A185351 (complement), A187794.

%K nonn

%O 1,2

%A _Timothy L. Tiffin_, Jul 13 2016