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A306950 Numbers m that divide A177754(m) = Sum_{k=1..m} uphi(k), where uphi is the unitary totient function (A047994). 3

%I #10 Aug 15 2021 21:51:55

%S 1,2,32,36,39,50,62,147,169,190,203,467,1035,1075,2174,2475,27047,

%T 28097,91087,181175,215795,539654,580160,668988,868879,2611450,

%U 14359486,118119399,1030191204,1109928219,2362155122

%N Numbers m that divide A177754(m) = Sum_{k=1..m} uphi(k), where uphi is the unitary totient function (A047994).

%C The unitary version of A048290.

%H Amiram Eldar, <a href="/A306950/a306950.txt">Table of n, a(n), A177754(a(n))/a(n) for n = 1..31.</a>

%e 32 is in the sequence since A177754(32) = 384 = 32 * 12 is divisible by 32.

%t uphi[1] = 1; uphi[n_] := Product[{p, e} = pe; p^e-1, {pe, FactorInteger[n]}]; seq={}; s = 0; Do[s = s + uphi[n]; If[Divisible[s,n], AppendTo[seq, n]], {n, 1, 10^6}]; seq (* after _Jean-François Alcover_ at A047994 *)

%Y Cf. A047994, A048290, A064611, A177754.

%K nonn,more

%O 1,2

%A _Amiram Eldar_, Mar 17 2019

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Last modified April 16 08:27 EDT 2024. Contains 371698 sequences. (Running on oeis4.)