

A111398


Numbers which are the cube roots of the product of their proper divisors.


6



1, 24, 30, 40, 42, 54, 56, 66, 70, 78, 88, 102, 104, 105, 110, 114, 128, 130, 135, 136, 138, 152, 154, 165, 170, 174, 182, 184, 186, 189, 190, 195, 222, 230, 231, 232, 238, 246, 248, 250, 255, 258, 266, 273, 282, 285, 286, 290, 296, 297
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OFFSET

1,2


COMMENTS

This sequence is actually the sequence of 4multiplicatively perfect numbers all of whose elements (>1) have prime signature {7}, {1,3} or {1,1,1}.


LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000


FORMULA

1 together with numbers with 8 divisors.  Vladeta Jovovic, Nov 12 2005


MATHEMATICA

Select[Range[300], Surd[Times@@Most[Divisors[#]], 3]==#&] (* Harvey P. Dale, Nov 16 2015 *)


PROG

(PARI) isok(n) = {prd = 1; fordiv(n, d, prd = prd*d); prd == n^4; } \\ Michel Marcus, Oct 04 2013


CROSSREFS

Cf. A048945, A111399. Essentially the same as A030626.
Cf. A030626, A007956.
Sequence in context: A109797 A129656 A048945 * A030626 A302571 A125639
Adjacent sequences: A111395 A111396 A111397 * A111399 A111400 A111401


KEYWORD

nonn


AUTHOR

Ant King, Nov 11 2005


EXTENSIONS

More terms from Michel Marcus, Oct 04 2013


STATUS

approved



