A015630 Augmented amicable pairs (larger member of each pair).

11697, 16005, 28917, 76245, 339825, 570405, 871585, 697851, 678376, 1340865, 2067625, 1823925, 1483785, 1899261, 2479065, 2580105, 4895241, 4740505, 5736445, 3171556, 4791916, 6516237, 4416976, 7524525, 9868075, 7589745

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• nice

Comments

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

The terms of the sequence are sorted in the order of the smaller (omitted) member of each pair. [Harvey P. Dale, Feb 29 2012]

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1159
• D. Moews, Augmented amicable pairs
• J. O. M. Pedersen, Tables of Aliquot Cycles [Broken link]
• J. O. M. Pedersen, Tables of Aliquot Cycles [Via Internet Archive Wayback-Machine]
• J. O. M. Pedersen, Tables of Aliquot Cycles [Cached copy, pdf file only]
• P. Pollack, Quasi-Amicable Numbers are Rare, J. Int. Seq. 14 (2011) # 11.5.2

Crossrefs

Cf. A007992.

Programs

Mathematica

aap[n_]:=Module[{p=Total[Most[Divisors[n]]]+1},If[p!=n&&n==Total[Most[ Divisors[p]]]+1,{p,n},0]]; Transpose[Union[Sort/@DeleteCases[aap/@ Range[10000000],0]]][[2]] (* Harvey P. Dale, Feb 29 2012 *)