1,2

R. K. Guy, Unsolved Problems in Number Theory, E11 and E12.

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

a(n) = A030126(n)-1. a(n) <= A003323(n)-2. - Max Alekseyev, Jan 12 2008

Cf. A030126.

Sequence in context: A113986 A149426 A042767 this_sequence A117882 A027123 A027125

Adjacent sequences: A045649 A045650 A045651 this_sequence A045653 A045654 A045655

nonn,hard,bref

Patric Ostergard (pat(AT)ultra.hut.fi, patric.ostergard(AT)hut.fi)