1,1
The sequence contains no further entries between 294 and 1600. - R. J. Mathar, May 26 2011
a(7) is 25 because the 25th multiply-perfect number A007691(25)=137438691328 is also the 7th perfect number A000396(7).
Cf. A000396, A007691.
Sequence in context: A124661 A134266 A062252 * A147791 A169647 A072467
Adjacent sequences: A153797 A153798 A153799 * A153801 A153802 A153803
more,nonn
Omar E. Pol (info(AT)polprimos.com), Jan 13 2009