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A290146 Records of the maxima of the unitary aliquot sequences of the numbers in A290145. 1
54, 90, 126, 162, 198, 378, 4950, 12978, 82278, 94218606, 8855754260391450, 645856907610421353834, 1350253136232108126126, 27709820863862780667438 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..14.

EXAMPLE

The unitary aliquot sequence of 174 is: 174, 186, 198, 162, 84, 76, 24, 12, 8, 1. Its maximum is 198 which larger than the maxima of all the aliquot sequences of the numbers below 174.

MATHEMATICA

usigma[n_] := If[n == 1, 1, Times @@ (1 + Power @@@ FactorInteger[n])];

g[n_] := If[n > 0, usigma[n] - n, 0]; f[n_] := NestWhileList[g, n, UnsameQ, All]; a = -1; rec = {}; Do[b = Length[f[n]] - 2; If[b > a, a = b; AppendTo[rec, b ]], {n, 10^6}] ; rec (* after Giovanni Resta at A034448 & Robert G. Wilson v at A098009 *)

CROSSREFS

Cf. A098008, A098009, A098010, A290145.

Sequence in context: A180150 A096512 A243542 * A071863 A045933 A088986

Adjacent sequences:  A290143 A290144 A290145 * A290147 A290148 A290149

KEYWORD

nonn,more

AUTHOR

Amiram Eldar, Jul 21 2017

STATUS

approved

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Last modified November 26 01:22 EST 2020. Contains 338631 sequences. (Running on oeis4.)