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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). 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified June 24 18:46 EDT 2021. Contains 345419 sequences. (Running on oeis4.)