      subroutine pot(f,k,l,n,jmin,im)
      dimension f(19,10,10)
      lam = l-1
      do 30 i=im,n
      j1=2*(i-1)+jmin
      do 30 j=i,n
      j2 = 2*(j-1) +jmin
      if(j2.le.j1+2) go to 10
      f(l,i,j)=0.
      go to 30
   10 continue
      if(j2.gt.j1) go to 20
      f(l,i,j)=-1.*(3.*float(lam)**2.-float(j1*(j1+1)))/((2.*float(j1)
     1+3.)*(2.*float(j1)-1.))
      go to 30
   20 continue
      f(l,i,j)=1.5*sqrt(float((j1+lam+2)*(j1+lam+1)*(j1-lam+2)*(j1-lam+1
     1))/float(((2*j1+5)*(2*j1+1))))/(2.*float(j1)+3.)
      f(l,j,i)=f(l,i,j)
   30 continue
      return
      end
