1,2

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.

Table of n, a(n) for n=1..77.

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

Sequence in context: A097010 A132999 A054027 * A080907 A127161 A129657

Adjacent sequences: A272975 A272976 A272977 * A272979 A272980 A272981

nonn

Timothy L. Tiffin, Jul 13 2016

approved