1,1

Numbers of the form 2^(2^m), 1<=m<=5 exist on the sequence. In other form, it is Product_{0<=i<=m} F_i + 1, 0<=m<=4, where F_i is Fermat prime 2^(2^i)+1

Cf. A047994, A117820.

Sequence in context: A122781 A024904 A139056 this_sequence A022802 A074997 A045959

Adjacent sequences: A120450 A120451 A120452 this_sequence A120454 A120455 A120456

nonn

Yasutsohi Kohmoto zbi74583(AT)boat.zero.ad.jp, Jul 20 2006