How to calculate Krawchouk polynomials

This code Calculate the polynomials of Krawchouk but when I buildt the image that dosen't work help :

    function [ Kw ] = polyK(N,p)%weighted Krawtchouk
    %POLYK Summary of this function goes here
    %   Detailed explanation goes here
    Kw=zeros(N,N);
    w(1)= exp(N*log(1-p)) ;%the weight fuction for x=0
    for x=1:1:N-1
    w(x+1)=((N-x)/(x+1))*((p/(1-p)))*w(x);
    end

    for n=2:1:N-1

    A=sqrt(((1-p)*(n+1))/(p*(N-n)));
    B=sqrt(((1-p)*(1-p)*(n+1)*n)/(p*p*(N-n)*(N-n+1)));
    for x=1:x:N
       Kw(1,x) =sqrt(w(x));
       Kw(2,x)=(1-(x/(p*N)))*sqrt(w(x));
       Kw(n+1,x)=((A*((N*p)-(2*n*p)+n-x)*Kw(n,x))-(B*n*(1-p)*Kw(n-1,x)))/(p*(n-N));
    end
    end

     end

[jenny jenny]

please heelp