设 p是适合p ≡1(mod6)的奇素数。根据二次Diophantine方程的性质,运用初等方法给出了方程 x3-8= py2有适合gcd(x ,y)=1的正整数解(x ,y)的新的判别条件。当 p ≡1或7(mod24)时,该方程无解;当p ≡13(mod24)时,该方程有解(x ,y)=(3r2+2,3rs),其中s是适合 ps2=3r4+6r2+1的正整数;当 p ≡19(mod24)时,该方程有解(x ,y)=(r2+2,rs),其中s是适合p s2= r4+6 r2+12的正整数。
Let p be an odd prime with p≡1(mod6) .By applying the properties of quadratic Diophantine equations and the elementary methods ,some new criterions for the positive integer solution (x ,y) of the equation x3 -8= p y2 w hen gcd(x ,y)=1 is given .If p≡1 or 7(mod 24) ,then the equation has no solu-tion .If p≡13(mod24) ,then the equation has the solution (x ,y)= (3 r2 +2 ,3 rs) ,w here s is a positive integer with ps2 =3r4 +6r2 +1 .If p≡19(mod24) ,then the equation has the solution (x ,y)= (r2 +2 , rs) ,where s is a positive integer with ps2 = r4 +6r2 +12 .