A066697 Numbers k such that Euler phi(k) / Carmichael lambda(k) = 18.

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

Links

Table of n, a(n) for n=1..41.

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

Cf. A000010, A002322.

Sequence in context: A044879 A060947 A182108 * A076338 A237620 A111344

Adjacent sequences: A066694 A066695 A066696 * A066698 A066699 A066700

Keyword

easy,nonn

Author

Randall L Rathbun, Jan 12 2002

Extensions

Corrected by T. D. Noe, Nov 01 2006

Status

approved