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A112756
Greatest prime factor of n-th number of the form 3^i*5^j.
4
1, 3, 5, 3, 5, 5, 3, 5, 5, 3, 5, 5, 5, 3, 5, 5, 5, 5, 3, 5, 5, 5, 5, 3, 5, 5, 5, 5, 5, 3, 5, 5, 5, 5, 5, 5, 3, 5, 5, 5, 5, 5, 5, 3, 5, 5, 5, 5, 5, 5, 5, 3, 5, 5, 5, 5, 5, 5, 5, 5, 3, 5, 5, 5, 5, 5, 5, 5, 5, 3, 5, 5, 5, 5, 5, 5, 5, 5, 5, 3, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 3, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 3, 5, 5, 5
OFFSET
1,2
LINKS
FORMULA
a(n) = A006530(A003593(n));
A112755(n) <= a(n) <= 5.
MATHEMATICA
s = {}; m = 12; Do[n = 5^k; While[n <= 5^m, AppendTo[s, n]; n *= 3], {k, 0, m}]; FactorInteger[#][[-1, 1]] & /@ Union[s] (* Amiram Eldar, Feb 07 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Sep 18 2005
STATUS
approved