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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A290142 Records of the maxima of the aliquot sequences of the numbers in A290141.

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%I A290142 #11 Jul 24 2017 12:35:39
%S A290142 16,21,22,55,259,759,32571,179931895322
%N A290142 Records of the maxima of the aliquot sequences of the numbers in A290141.
%C A290142 a(8) was calculated by D. H. Lehmer.
%e A290142 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.
%t A290142 g[n_] := If[n > 0, DivisorSigma[1, n] - n, 0]; f[n_] := NestWhileList[g, n, UnsameQ, All]; rec = {}; a = -1; seq = {}; Do[b = Max[Drop[f[n], 1]];
%t A290142 If[b > a, a = b; AppendTo[rec, b]], {n, 2, 275}] ; rec (* after _Robert G. Wilson v_ at A098009 *)
%Y A290142 Cf. A008888, A098008, A098009, A098010, A290141.
%K A290142 nonn,more
%O A290142 1,1
%A A290142 _Amiram Eldar_, Jul 21 2017