A066934 Composite solutions of phi(n)==1 (mod bigomega(n)) where phi(n)=A000010(n) is the Euler totient function and bigomega(n)=A001222(n) is the number of prime divisors of n (counted with multiplicity).

8, 12, 32, 48, 75, 108, 110, 125, 128, 170, 192, 208, 230, 280, 290, 312, 363, 368, 374, 405, 410, 420, 470, 506, 530, 552, 590, 638, 680, 684, 688, 702, 710, 782, 830, 848, 867, 890, 902, 935, 980, 986, 1008, 1010, 1020, 1032, 1034, 1044, 1070, 1080, 1088

Offset

1,1

Comments

Trivially, no prime is a solution of the congruence.

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

Mathematica

bigomega[n_] := Plus@@Last/@FactorInteger[n]; Select[Range[2, 1100], !PrimeQ[ # ]&&Mod[EulerPhi[ # ]-1, bigomega[ # ]]==0&]
Select[Range[1100], CompositeQ[#]&&Mod[EulerPhi[#], PrimeOmega[#]]==1&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 14 2018 *)

Prog

(PARI) { n=0; for (m=2, 10^10, if (eulerphi(m) % bigomega(m) == 1, write("b066934.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, Apr 08 2010

Crossrefs

Sequence in context: A117802 A083485 A217156 * A137148 A211778 A045018

Adjacent sequences: A066931 A066932 A066933 * A066935 A066936 A066937

Keyword

nonn

Author

Benoit Cloitre, Jan 24 2002

Extensions

Edited by Dean Hickerson, Jan 27 2002

COMMENT corrected by Harry J. Smith, Apr 08 2010

Status

approved