A290141 Numbers n that have a record maximum (> n) in their aliquot sequence.

12, 18, 20, 24, 30, 102, 120, 138

Offset

1,1

Comments

Maximum term in the aliquot sequence of n is considered only if it is larger than n.

The record values are in A290142.

Links

Table of n, a(n) for n=1..8.

Example

The aliquot sequence of 30 is: 30, 42, 54, 66, 78, 90, 144, 259, 45, 33, 15, 9, 4, 3, 1. The maximum is 259 which is larger than 30, and larger than the maxima of all the aliquot sequences of the numbers below 30.

Mathematica

g[n_] := If[n > 0, DivisorSigma[1, n] - n, 0]; f[n_] := NestWhileList[g, n, UnsameQ, All]; seq = {}; a = -1; seq = {}; Do[b = Max[Drop[f[n], 1]];  If[b > a, a = b; AppendTo[seq, n]], {n, 2, 275}]; seq (* after Robert G. Wilson v at A098009 *)

Crossrefs

Cf. A098008, A098009, A098010, A290142.

Sequence in context: A005101 A124626 A231547 * A087245 A342100 A153501

Adjacent sequences: A290138 A290139 A290140 * A290142 A290143 A290144

Keyword

nonn,more

Author

Amiram Eldar, Jul 21 2017

Status

approved