A366522 Largest squarefree divisor of n which is < sqrt(n), for n >= 2; a(1) = 1.
1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 3, 2, 1, 3, 1, 2, 3, 2, 1, 3, 1, 2, 3, 2, 1, 5, 1, 2, 3, 2, 5, 3, 1, 2, 3, 5, 1, 6, 1, 2, 5, 2, 1, 6, 1, 5, 3, 2, 1, 6, 5, 7, 3, 2, 1, 6, 1, 2, 7, 2, 5, 6, 1, 2, 3, 7, 1, 6, 1, 2, 5, 2, 7, 6, 1, 5, 3, 2, 1, 7, 5, 2, 3, 2, 1, 6, 7, 2, 3, 2, 5, 6, 1, 7, 3, 5
Offset: 1
Keywords
Links
- Andrew Howroyd, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
Join[{1}, Table[Last[Select[Divisors[n], # < Sqrt[n] && SquareFreeQ[#] &]], {n, 2, 100}]] -
PARI
a(n) = {my(m=1); fordiv(n, d, if(d^2 < n && issquarefree(d), m=max(m,d))); m} \\ Andrew Howroyd, Oct 11 2023