1,1
a(7) is 25 because the 25th multiply-perfect number A007691(25)=137438691328 is also the 7th perfect number A000396(7).
cF. A000396, A007691.
Adjacent sequences: A153797 A153798 A153799 this_sequence A153801 A153802 A153803
Sequence in context: A038917 A134266 A062252 this_sequence A147791 A072467 A062326
more,nonn
Omar E. Pol (info(AT)polprimos.com), Jan 13 2009
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