/* bc program kronecker
 * needs jacobi.
 * using Henri Cohen's definition in the case n>=1, 
 * this returns 0 if gcd(d,n)>1. Otherwise if n is even and 2^t||n,
 * it returns jacobi(2,|d|) times jacobi(d,n/2^t).
 */
define kronecker(d,n){
auto ks,t,j,temp,dn,rn

dn=d%2
rn=n%2
if(dn==0 && rn==0){
   return(0)
}
ks=1
if(rn==0){
  t=0
  while(1){
      n=n/2
      t=t+1
      if(n%2){
        break
      }
  }
  temp=mod(d,8)
  if((temp==3 ||temp==5) && t%2){
     ks=-ks
  }
}
j=jacobi(d,n)
return(ks*j)
}