1,1

Numbers of the form a^b where a is a number that is not a perfect power and b is a perfect number (equal to the sum of its divisors). In other words, A007916^A000396.

Table of n, a(n) for n=1..20.

64 qualifies because its roots are 2, 4, and 8 and 2*4*8=64.

Cf. A007916, A000396.

Sequence in context: A001014 A050753 A074154 * A153160 A113851 A046455

Adjacent sequences: A240842 A240843 A240844 * A240846 A240847 A240848

more,nonn

J. Lowell, Apr 13 2014

approved