OFFSET
1,2
COMMENTS
A065428 is a subsequence.
No more such numbers up to 10^6.
Observe that many of these numbers are of the form k^2-1. Why?
PROG
(PARI) for(n=1, 10^6, q=1; for(x=1, n-1, if(isprime(component(Mod(x, n)^4, 2)), q=0; break())); if(q, print1(n, ", ")));
(PARI) {a(n) = my(c, m); if(n<=1, n==1, c=1; m=1; while( c<n, m++; c += prod(x=1, m-1, !isprime( lift( Mod(x, m)^4 ) ) ) ); m)}; /* Michael Somos, Jan 07 2011 */
CROSSREFS
KEYWORD
nonn
AUTHOR
Joerg Arndt, Jan 07 2011
STATUS
approved