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

1,6

Links

Andrew Howroyd, Table of n, a(n) for n = 1..10000

Mathematica

Join[{1}, Table[Last[Select[Divisors[n], # < Sqrt[n] && SquareFreeQ[#] &]], {n, 2, 100}]]

Prog

(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

Crossrefs

Cf. A007947, A060775, A089384, A366521.

Sequence in context: A346089 A302776 A366510 * A345934 A060775 A355368

Adjacent sequences: A366519 A366520 A366521 * A366523 A366524 A366525

Keyword

nonn

Author

Ilya Gutkovskiy, Oct 11 2023

Status

approved