OFFSET
1,4
LINKS
Wikipedia, Geometric mean
EXAMPLE
The a(216) = 5 factorizations:
(2*4*27)
(3*3*24)
(3*6*12)
(6*6*6)
(216)
The a(729) = 8 factorizations:
(3*3*3*3*3*3)
(3*3*81)
(3*9*27)
(3*243)
(9*9*9)
(9*81)
(27*27)
(729)
MATHEMATICA
facs[n_]:=If[n<=1, {{}}, Join@@Table[Map[Prepend[#, d]&, Select[facs[n/d], Min@@#>=d&]], {d, Rest[Divisors[n]]}]];
Table[Length[Select[facs[n], IntegerQ[Mean[#]]&&IntegerQ[GeometricMean[#]]&]], {n, 2, 100}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jul 16 2019
STATUS
approved