OFFSET
1,1
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..18157 (first 2000 terms from Enrique PĂ©rez Herrero)
MATHEMATICA
Select[Range[204], ! Divisible[EulerPhi[#], DivisorSigma[0, #]] &]
PROG
(PARI) is(k) = {my(f = factor(k), d = numdiv(f), p = eulerphi(f)); p % d; } \\ Amiram Eldar, May 15 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved