iscongruent(n)=
{
i=0;j=0;\
if(issquare(n),print(n," is not a congruent number"),\
m=core(n);\
if(m%8==5||m%8==6||m%8==7,print(n," is a congruent number"),\
if(m%2,\
for(x=-round(sqrt(m/2)),round(sqrt(m/2)),\
 for(y=-round(sqrt(m)),round(sqrt(m)),\
  for(z=-round(sqrt(m/8)),round(sqrt(m/8)),\
   if(2*x^2+y^2+8*z^2==m,i++,))));\
for(x=-round(sqrt(m/2)),round(sqrt(m/2)),\
 for(y=-round(sqrt(m)),round(sqrt(m)),\
  for(z=-round(sqrt(m/32)),round(sqrt(m/32)),\
   if(2*x^2+y^2+32*z^2==m,j++,))));\
if(i==2*j,print(n," is a congruent number"),print(n," is not a congruent number")),\
k=m/2;\
for(x=-round(sqrt(k/4)),round(sqrt(k/4)),\
 for(y=-round(sqrt(k)),round(sqrt(k)),\
  for(z=-round(sqrt(k/8)),round(sqrt(k/8)),\
   if(4*x^2+y^2+8*z^2==k,i++,))));\
for(x=-round(sqrt(k/4)),round(sqrt(k/4)),\
 for(y=-round(sqrt(k)),round(sqrt(k)),\
  for(z=-round(sqrt(k/32)),round(sqrt(k/32)),\
   if(4*x^2+y^2+32*z^2==k,j++,))));\
if(i==2*j,print(n," is a congruent number"),print(n," is not a congruent number")))))
}

addhelp(iscongruent , "iscongruent(n) : determines if n is a congruent number (assuming BSD).")

printp("iscongruent(n) : determines if n is a congruent number (assuming BSD).")