A336488 Values taken by all the Jordan totient functions J_k(m) for k >= 1 and m >= 1.

1, 2, 3, 4, 6, 7, 8, 10, 12, 15, 16, 18, 20, 22, 24, 26, 28, 30, 31, 32, 36, 40, 42, 44, 46, 48, 52, 54, 56, 58, 60, 63, 64, 66, 70, 72, 78, 80, 82, 84, 88, 92, 96, 100, 102, 104, 106, 108, 110, 112, 116, 120, 124, 126, 127, 128, 130, 132, 136, 138, 140, 144, 148

Offset

1,2

Comments

The asymptotic density of this sequence is 0 (Rao and Murty, 1979).

First differs from A221178 at n = 75, since a(75) = J_3(6) = 182 is not a term of A221178.

Links

Table of n, a(n) for n=1..63.

R. Sita Rama Chandra Rao and G. Sri Rama Chandra Murty, On a theorem of Niven, Canadian Mathematical Bulletin, Vol 22, No. 1 (1979), pp. 113-115.

Mathematica

phiQ[m_] := Select[Range[m + 1, 2 m*Product[(1 - 1/(k*Log[k]))^(-1), {k, 2, DivisorSigma[0, m]}]], EulerPhi[#] == m &, 1] != {}; jor[k_, n_] := DivisorSum[n, #^k*MoebiusMu[n/#] &]; jorval[k_, mx_] := jor[k, #] & /@ Range[Floor@Surd[mx*Zeta[k], k]]; mx = 300; Select[Union @ Flatten[{Select[Range[mx], phiQ], jorval[#, mx] & /@ Range[2, Floor[Log2[mx]]]}], # <= mx &] (* using code by Jean-François Alcover at A002202 *)

Crossrefs

A002202 is a subsequence.

Cf. A000010, A007434, A059376, A059377, A059378, A059379, A059380, A069091, A069092, A069093, A069094, A069095, A221178.

Similar sequence: A211347.

Sequence in context: A335041 A335042 A257282 * A221178 A080389 A359755

Adjacent sequences: A336485 A336486 A336487 * A336489 A336490 A336491

Keyword

nonn

Author

Amiram Eldar, Jul 23 2020

Status

approved