1,2

Do[ If[ PrimeQ[n + 1] && PrimeQ[n^2 + 1] && PrimeQ[n^4 + 1] && PrimeQ[n^8 + 1] && PrimeQ[n^16 + 1], Print[n]], {n, 1, 10^7}]

Sequence in context: A124362 A058435 A151606 this_sequence A158346 A018854 A139181

Adjacent sequences: A070691 A070692 A070693 this_sequence A070695 A070696 A070697

nonn

Robert G. Wilson v (rgwv(AT)rgwv.com), May 13 2002