OFFSET
1,1
COMMENTS
There seem to be no such numbers (bit sizes) such that any 4-bit or 5-bit number is composite, up to n around 200.
LINKS
T. D. Noe, Table of n, a(n) for n=1..265
PROG
(PARI) for(n=2, 1000, f=0; for(i=1, n-1, t=2^n+2^i+1; if(isprime(t), f=1; break)); if(!f, print1(n", ")))
CROSSREFS
KEYWORD
nonn
AUTHOR
Ralf Stephan, Apr 21 2003
STATUS
approved