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.

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

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%I A306950 #10 Aug 15 2021 21:51:55
%S A306950 1,2,32,36,39,50,62,147,169,190,203,467,1035,1075,2174,2475,27047,
%T A306950 28097,91087,181175,215795,539654,580160,668988,868879,2611450,
%U A306950 14359486,118119399,1030191204,1109928219,2362155122
%N A306950 Numbers m that divide A177754(m) = Sum_{k=1..m} uphi(k), where uphi is the unitary totient function (A047994).
%C A306950 The unitary version of A048290.
%H A306950 Amiram Eldar, <a href="/A306950/a306950.txt">Table of n, a(n), A177754(a(n))/a(n) for n = 1..31.</a>
%e A306950 32 is in the sequence since A177754(32) = 384 = 32 * 12 is divisible by 32.
%t A306950 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 A306950 Cf. A047994, A048290, A064611, A177754.
%K A306950 nonn,more
%O A306950 1,2
%A A306950 _Amiram Eldar_, Mar 17 2019