OFFSET
1,2
COMMENTS
Contains 2 * terms t of A350777 such that (t-3)/phi(t) = 2. - Max Alekseyev, Oct 26 2023
MATHEMATICA
Select[Range[20000000], !PrimeQ[#/2] && Divisible[#+2, EulerPhi[#]+2]&]
PROG
(PARI) for(n=1, 1e5, if((n+2)%(eulerphi(n)+2)==0&&(n%2||!isprime(n/2)), print1(n", "))) \\ Charles R Greathouse IV, Mar 02 2012
CROSSREFS
KEYWORD
nonn,more,hard
AUTHOR
José María Grau Ribas, Feb 19 2012
EXTENSIONS
a(4)-a(5) from Max Alekseyev, Nov 06 2023
STATUS
approved