function ab=sr_charlier_ops(dig,N,a)
%SR_CHARLIER_OPS Recurrence coefficients for the Charlier 
%orthogonal polynomials.
%   AB=SR_CHARLIER_OPS(DIG,N,A) generates in DIG-digit arithmetic 
%   the Nx2 array AB of the first N recurrence coefficients for
%   the weight function w(k)=exp(-A)*A^k/k!, k=0:Inf, A>0.

digits(dig); 
ab=vpa(zeros(N,2)); sa=vpa(a); s1=vpa(1);
k=vpa(1:N);
ab(:,1)=k-1+sa;
k=vpa(1:N-1);
ab(:,2)=[s1 sa*k]';
