cp's OEIS Frontend

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.

A333612 Numbers at which the sum of the iterated infinitary totient function (A091732) attains a record.

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%I A333612 #10 Mar 29 2020 02:11:54
%S A333612 1,2,3,4,5,9,11,13,16,17,29,37,47,49,53,81,101,107,113,149,173,197,
%T A333612 257,389,401,509,529,531,557,593,677,701,747,773,829,963,977,1109,
%U A333612 1297,1493,1675,1733,1901,2417,2761,2837,3089,3313,3329,3413,3467,3677,3803,3989
%N A333612 Numbers at which the sum of the iterated infinitary totient function (A091732) attains a record.
%C A333612 Analogous to A181659 with the infinitary totient function A091732 instead of the Euler totient function phi (A000010).
%C A333612 The corresponding record values are 0, 1, 3, 6, 10, 14, 20, 21, 29, 45, ... (see the link for more values).
%H A333612 Amiram Eldar, <a href="/A333612/b333612.txt">Table of n, a(n) for n = 1..500</a>
%H A333612 Amiram Eldar, <a href="/A333612/a333612.txt">Table of n, a(n), A333611(a(n)) for n=1..500</a>
%t A333612 f[p_, e_] := p^(2^(-1 + Position[Reverse @ IntegerDigits[e, 2], 1])); iphi[1] = 1; iphi[n_] := Times @@ (Flatten@(f @@@ FactorInteger[n]) - 1); s[n_] := Plus @@ NestWhileList[iphi, n, # != 1 &] - n; seq = {}; smax = -1; Do[s1 = s[n];  If[s1 > smax, smax = s1; AppendTo[seq, n]], {n, 1, 10^5}]; seq
%Y A333612 Cf. A091732, A181659, A330400, A331407, A333611.
%K A333612 nonn
%O A333612 1,2
%A A333612 _Amiram Eldar_, Mar 28 2020