A331958 - OEIS

%I #12 Feb 05 2020 08:58:43

%S 0,1,1,1,2,1,1,1,2,3,1,1,2,2,2,1,4,2,3,3,2,2,2,2,2,5,2,3,3,3,2,2,4,4,

%T 2,2,6,3,3,3,2,2,2,2,2,3,3,3,4,7,5,5,2,2,3,3,3,3,3,3,2,2,2,3,8,4,4,4,

%U 3,3,2,2,6,6,3,5,5,5,3,3,4,9,4,4,4,3,3

%N a(n)^2 is the greatest square number of the form floor(n/k) where k > 0.

%H Rémy Sigrist, <a href="/A331958/b331958.txt">Table of n, a(n) for n = 0..10000</a>

%F a(n)^2 = floor(n/A331953(n))

%F a(n^2) = n.

%F a(2*n^2) = n.

%e For n = 12:

%e - floor(12/1) = 12 is not a square number,

%e - floor(12/2) = 6 is not a square number,

%e - floor(12/3) = 4 is the square of 2,

%e - hence a(12) = 2.

%o (PARI) a(n) = for (k=1, oo, if (issquare(n\k), return (sqrtint(n\k))))

%Y Cf. A331953.

%K nonn

%O 0,5

%A _Rémy Sigrist_, Feb 02 2020