(7-1)(7+1)(7^2+1)(7^4+1)(7^8+1)
=(7^2-1)(7^2+1)(7^4+1)(7^8+1)
=(7^4-1)(7^4+1)(7^8+1)
=(7^8-1)(7^8+1)
=7^16-1
6=7-1
6(7+1)(7^2+1)(7^4+1)(7^8+1)
=(7-1)(7+1)(7^2+1)(7^4+1)(7^8+1)
=(7^2-1)(7^2+1)(7^4+1)(7^8+10
=(7^4-1)(7^4+1)(7^8+1)
=(7^8-1)(7^8+1)
=7^16-1