A369334 - OEIS

%I #5 Jan 21 2024 02:13:48

%S 72,144,168,360,450,480,864,990,1200,1404,1568,1600,1800,2040,2160,

%T 2520,2646,3150,3360,3600,3780,4050,4800,5184,5400,5520,5880,5940,

%U 6720,7056,7200,7350,7800,7938,8550,8640,8694,8712,8976,9408,9450,9504,10416,11550,11760,12000,12600,12960,13230,14112,14850,15288,16128,16200,16560,16562,17640,18000,18144,18216

%N Positive integers m such that there exist distinct pairs (a,b) and (c,d) with a <= b, c <= d, gcd(a,b,c,d) = 1, and m = a*b*(c+d) = (a+b)*c*d.

%C Note that a*b*(c+d) = (a+b)*c*d is equivalent to 1/a + 1/b = 1/c + 1/d.

%Y Cf. A369333.

%K nonn

%O 1,1

%A _Max Alekseyev_, Jan 20 2024