1,1

Let f(n) = 1 + sum of aliquot divisors of n; these are pairs (n,m) with f(n)=m, f(m)=n.

D. Moews, Augmented amicable pairs

J. O. M. Pedersen, Tables of Aliquot Cycles

Cf. A015630.

Sequence in context: A114131 A144491 A152388 this_sequence A033288 A057880 A151967

Adjacent sequences: A007989 A007990 A007991 this_sequence A007993 A007994 A007995

nonn,nice

N. J. A. Sloane (njas(AT)research.att.com).