1,1

A064078(a(n)) is composite number. The sequence have a positive density since

contains, in particular, numbers of the form 8n+20 for n>=1 (C.Pomerance, private correspondence). Since, e. g., 38 is not in the sequence, then there is not an overpseudoprime m such that ord_m(2)=38.

Cf. A141232 A002326 A064078 A122929.

Sequence in context: A032663 A119815 A046624 this_sequence A061752 A122259 A157173

Adjacent sequences: A143581 A143582 A143583 this_sequence A143585 A143586 A143587

nonn

Vladimir Shevelev (shevelev(AT)bgu.ac.il), Aug 25 2008