cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A366522 Largest squarefree divisor of n which is < sqrt(n), for n >= 2; a(1) = 1.

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%I A366522 #12 Jan 04 2024 18:57:33
%S A366522 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,
%T A366522 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,
%U A366522 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
%N A366522 Largest squarefree divisor of n which is < sqrt(n), for n >= 2; a(1) = 1.
%H A366522 Andrew Howroyd, <a href="/A366522/b366522.txt">Table of n, a(n) for n = 1..10000</a>
%t A366522 Join[{1}, Table[Last[Select[Divisors[n], # < Sqrt[n] && SquareFreeQ[#] &]], {n, 2, 100}]]
%o A366522 (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
%Y A366522 Cf. A007947, A060775, A089384, A366521.
%K A366522 nonn
%O A366522 1,6
%A A366522 _Ilya Gutkovskiy_, Oct 11 2023