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A366524
Largest square divisor of n which is < sqrt(n), for n >= 2; a(1) = 1.
3
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 9, 1, 4, 1, 1, 1, 4, 1, 1, 9, 4
OFFSET
1,20
LINKS
MATHEMATICA
Join[{1}, Table[Last[Select[Divisors[n], # < Sqrt[n] && IntegerQ[Sqrt[#]] &]], {n, 2, 100}]]
PROG
(PARI) a(n) = {my(m=1); fordiv(sqrtint(n/core(n)), d, if(d^4 < n, m=max(m, d))); m^2} \\ Andrew Howroyd, Oct 11 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Oct 11 2023
STATUS
approved