OFFSET
1,1
EXAMPLE
p = 5: phi(4) = phi(6) = 2, thus 5 is a term;
p = 19: phi(16) + phi(17) + phi(18) = phi(20) + phi(21) + phi(22) = 30, thus 19 is a term.
PROG
(PARI) isok(p) = if (isprime(p), my(k=primepi(p)); for (i=1, k-1, if (sum(j=1, i, eulerphi(p-j)) == sum(j=1, i, eulerphi(p+j)), return(1)); ); ); \\ Michel Marcus, Jan 03 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Ctibor O. Zizka, Jan 03 2023
EXTENSIONS
More terms from Michel Marcus, Jan 03 2023
STATUS
approved