highest prime factor of 2^396 +1

• 2^396+1 is a prime no
  2^4+1=17 is a prime no
  2^8+1=257 is a prime no
  2^12+1=4097 is a prime no
  logic is
  2^n+1 = prime no (when n is factor of 4)
• 12 years agoHelpfull: Yes(0) No(0)