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

1,3

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)

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 *)

Prog

(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

Crossrefs

Cf. A001065, A034090.

Sequence in context: A301287 A310133 A346878 * A278812 A111717 A181911

Adjacent sequences: A034088 A034089 A034090 * A034092 A034093 A034094

Keyword

nonn,nice

Author

N. J. A. Sloane, J. Lowell

Extensions

More terms from Erich Friedman.

Status

approved