http://en.wikipedia.org/wiki/Laguerre_polynomials
http://wenku.baidu.com/view/7d013c8c680203d8ce2f24ee.html
how to evaluate to equation (5.9) in page 195 from rodrigues formula?
rodrigues := exp(x)*(x^alpha)/n!*Diff(exp(-x)*(x^(n+alpha)), x$n);
rodrigues := subs(x=2*p, rodrigues);
rodrigues := subs(alpha=1/2, rodrigues);
rodrigues := simplify(rodrigues);
rodrigues := simplify(collect(rodrigues,(exp(p))^2));
