A290146 - OEIS

%I #10 Jul 24 2017 12:36:39

%S 54,90,126,162,198,378,4950,12978,82278,94218606,8855754260391450,

%T 645856907610421353834,1350253136232108126126,27709820863862780667438

%N Records of the maxima of the unitary aliquot sequences of the numbers in A290145.

%e 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.

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

%t 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 *)

%Y Cf. A098008, A098009, A098010, A290145.

%K nonn,more

%O 1,1

%A _Amiram Eldar_, Jul 21 2017