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 A240845 Numbers n equal to the product of all of their integral proper roots (defined as numbers k in the range 1 < k < n such that k^j = n for some j). 0
 64, 729, 15625, 46656, 117649, 1000000, 1771561, 2985984, 4826809, 7529536, 11390625, 24137569, 34012224, 47045881, 64000000, 85766121, 113379904, 148035889, 191102976, 268435456 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 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. LINKS EXAMPLE 64 qualifies because its roots are 2, 4, and 8 and 2*4*8=64. CROSSREFS Cf. A007916, A000396. Sequence in context: A001014 A050753 A074154 * A153160 A113851 A046455 Adjacent sequences:  A240842 A240843 A240844 * A240846 A240847 A240848 KEYWORD more,nonn AUTHOR J. Lowell, Apr 13 2014 STATUS approved

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Last modified January 20 02:57 EST 2019. Contains 319323 sequences. (Running on oeis4.)