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1,1

This is a subsequence of the sequence of multiply perfect numbers A007691.

The prime values of sigma(n) / n are A219545.

Table of n, a(n) for n=1..22.

Cf. A007691, A219545.

Sequence in context: A002694 A007691 A260508 * A006516 A171476 A171496

Adjacent sequences: A065994 A065995 A065996 * A065998 A065999 A066000

nonn

Joseph L. Pe, Dec 10 2001

Terms a(10) to a(14) from Jonathan Sondow, Nov 22 2012

Extended by T. D. Noe, Nov 26 2012

approved