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A306950 Numbers n such that n divides A177754(n) = Sum_{k=1..n} uphi(k), where uphi is the unitary totient function (A047994). 2
1, 2, 32, 36, 39, 50, 62, 147, 169, 190, 203, 467, 1035, 1075, 2174, 2475, 27047, 28097, 91087, 181175, 215795, 539654, 580160, 668988, 868879, 2611450, 14359486, 118119399, 1030191204, 1109928219, 2362155122 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The unitary version of A048290.

LINKS

Table of n, a(n) for n=1..31.

Amiram Eldar, Table of n, a(n), A177754(a(n))/a(n) for n=1..31.

EXAMPLE

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

MATHEMATICA

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-Fran├žois Alcover at A047994 *)

CROSSREFS

Cf. A047994, A048290, A064611, A177754.

Sequence in context: A166487 A004842 A022378 * A193419 A160557 A103028

Adjacent sequences:  A306947 A306948 A306949 * A306951 A306952 A306953

KEYWORD

nonn,more

AUTHOR

Amiram Eldar, Mar 17 2019

STATUS

approved

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Last modified November 13 00:25 EST 2019. Contains 329083 sequences. (Running on oeis4.)