A034091 Records for sum of proper divisors function A001065.

0, 1, 3, 6, 7, 8, 16, 21, 22, 36, 42, 55, 76, 108, 123, 140, 144, 156, 172, 240, 259, 312, 366, 384, 504, 531, 568, 656, 810, 924, 1032, 1056, 1140, 1260, 1356, 1698, 2040, 2088, 2216, 2520, 2644, 3108, 3474, 3480, 4272, 4572, 4844, 5280, 5304, 5412, 6840

Offset: 1

Author

N. J. A. Sloane, J. Lowell

Keywords

• nonn
• nice

Links

• Don Reble, Table of n, a(n) for n = 1..6524 (first 372 terms from _T. D. Noe_, terms 373 to 1000 from _Donovan Johnson_, terms 1001 to 2750 from Robert G. Wilson v)

Crossrefs

Cf. A001065, A034090.

Programs

Mathematica

With[{list1=DeleteDuplicates[Array[DivisorSigma[1, #]-#&, 3000, 0]]}, list2 = {}; Table[If[list1[[n]]>Max[list2], AppendTo[list2, list1[[n]]]], {n, Length[ list1]}]; list2] (* Harvey P. Dale, Dec 30 2011 *)
t = {0}; n = 1; mx = 0; While[Length[t] < 100, n++; s = DivisorSigma[1, n] - n; If[s > mx, mx = s; AppendTo[t, mx]]]; t (* T. D. Noe, Feb 23 2012 *)
DeleteDuplicates[Array[DivisorSigma[1,#]-#&,3000],GreaterEqual] (* Harvey P. Dale, Aug 20 2022 *)

PARI

r=0; for(n=1,1e9, t=sigma(n)-n; if(t>r, r=t; print1(t", "))) \\ Charles R Greathouse IV, Feb 09 2017

Extensions

More terms from Erich Friedman.