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Numbers which are the cube roots of the product of their proper divisors.
7

%I #10 Nov 16 2015 07:43:41

%S 1,24,30,40,42,54,56,66,70,78,88,102,104,105,110,114,128,130,135,136,

%T 138,152,154,165,170,174,182,184,186,189,190,195,222,230,231,232,238,

%U 246,248,250,255,258,266,273,282,285,286,290,296,297

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

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

%H Harvey P. Dale, <a href="/A111398/b111398.txt">Table of n, a(n) for n = 1..1000</a>

%F 1 together with numbers with 8 divisors. - _Vladeta Jovovic_, Nov 12 2005

%t Select[Range[300],Surd[Times@@Most[Divisors[#]],3]==#&] (* _Harvey P. Dale_, Nov 16 2015 *)

%o (PARI) isok(n) = {prd = 1; fordiv(n, d, prd = prd*d); prd == n^4;} \\ _Michel Marcus_, Oct 04 2013

%Y Cf. A048945, A111399. Essentially the same as A030626.

%Y Cf. A030626, A007956.

%K nonn

%O 1,2

%A _Ant King_, Nov 11 2005

%E More terms from _Michel Marcus_, Oct 04 2013