%I #29 Oct 28 2022 14:22:49

%S 0,0,1,1,0,2,0,1,1,1,0,8,0,0,4,1,0,2,0,4,3,0,0,9,0,0,1,2,0,7,0,1,2,0,

%T 1,8,0,0,1,4,0,5,0,1,5,0,0,9,0,1,1,1,0,2,1,4,1,0,0,23,0,0,3,1,1,4,0,1,

%U 1,2,0,10,0,0,4,1,0,4,0,4,1,0,0,17,0,0,1,1,0,8

%N a(n) = number of integers of the form (n*k)^2/(k^2 - n^2).

%C k needs to be checked only up through n^2+1 since beyond this n^2 < (n*k)^2/(k^2 - n^2) < n^2 + 1 and thus can't be an integer. - _Micah Manary_, Aug 27 2022

%H Micah Manary, <a href="/A152492/b152492.txt">Table of n, a(n) for n = 1..1000</a>

%o (PARI) a(n) = sum(k=1, n^2+1, if (k!=n, denominator((n*k)^2/(k^2 - n^2))==1)); \\ _Michel Marcus_, Oct 28 2022

%Y Cf. A071086, A146567, A146566, A146564.

%K easy,nonn

%O 1,6

%A _Ctibor O. Zizka_, Dec 06 2008

%E More terms from _Micah Manary_, Aug 07 2022