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A066697
Numbers k such that Euler phi(k) / Carmichael lambda(k) = 18.
0
513, 703, 999, 1026, 1387, 1406, 1539, 1971, 1998, 2071, 2413, 2774, 2943, 2997, 3078, 3097, 3429, 3439, 3781, 3942, 4142, 4401, 4617, 4699, 4826, 4887, 5149, 5373, 5833, 5886, 5913, 5994, 6031, 6194, 6858, 6878, 7201, 7317, 7363, 7543, 7562
OFFSET
1,1
MATHEMATICA
Select[Range[8000], EulerPhi[#]/CarmichaelLambda[#]==18&] (* Harvey P. Dale, Jun 06 2018 *)
PROG
(PARI) {cmf(f)=if( ((f[1]==2)&&(f[2]>2)), eulerphi(f[1]^f[2])/2, eulerphi(f[1]^f[2])) } {cl(f)= k=factor(f); l=1; for(x=1, omega(f), l=lcm(l, cmf([k[x, 1], k[x, 2]]))); l } {A0(n)=eulerphi(n)/cl(n)} for(x=1, 10001, if(A0(x)==18, print1(x, ", ")))
(PARI) isok(k) = eulerphi(k)/lcm(znstar(k)[2]) == 18; \\ Michel Marcus, May 25 2022
CROSSREFS
Sequence in context: A044879 A060947 A182108 * A076338 A237620 A111344
KEYWORD
easy,nonn
AUTHOR
Randall L Rathbun, Jan 12 2002
EXTENSIONS
Corrected by T. D. Noe, Nov 01 2006
STATUS
approved