0,1

No other solutions below 4.10^18 (probably finite) - Dec 15 1999

Cf. A028868, A028865, A028866.

Sequence in context: A068708 A063248 A027522 this_sequence A073172 A111443 A051499

Adjacent sequences: A028866 A028867 A028868 this_sequence A028870 A028871 A028872

nonn,base,hard

Patrick De Geest (pdg(AT)worldofnumbers.com)