function ab=sr_laguerre(dig,N,a)
%SR_LAGUERRE Recurrence coefficients for generalized Laguerre 
%polynomials.
%   AB=SR_LAGUERRE(DIG,N,A) generates in DIG-digit arithmetic
%   the Nx2 array AB of the first N recurrence coefficients for
%   generalized Laguerre polynomials orthogonal on [0,Inf] with
%   respect to the weight function w(x)=x^A*exp(-x), A>-1.
 
digits(dig);
if nargin<3, a=0; end
if((N<=0)|(a<=-1)) error('parameter(s) out of range'), end
nu=vpa(a+1); mu=gamma(vpa(a+1));
if N==1, ab=[nu mu]; return, end
N=N-1; n=1:N; na=2*n+nu; nb=n.*vpa(n+a);
A=[nu na]; B=[mu nb];
ab=[A' B'];
