r̲e̲a̲l̲ p̲r̲o̲c̲e̲d̲u̲r̲e̲ La(n, X);
   c̲o̲m̲m̲e̲n̲t̲ This procedure computes the Laguerre polynomial
     Ln(X) = exp(X) * (d^n/dX^n(exp(-X)) for any
     given real argument X, and any order, n, by
     the recursion formula below;
   i̲n̲t̲e̲g̲e̲r̲ n;
     r̲e̲a̲l̲ X;
b̲e̲g̲i̲n̲
   r̲e̲a̲l̲ a, b, c;
   i̲n̲t̲e̲g̲e̲r̲ i;
   a := 1;
   b := 1 - X;
   i̲f̲ n = 0 t̲h̲e̲n̲ c := a e̲l̲s̲e̲ i̲f̲ n = 1 t̲h̲e̲n̲
     c := b e̲l̲s̲e̲ f̲o̲r̲ i := 1 s̲t̲e̲p̲ 1 u̲n̲t̲i̲l̲ n - 1 d̲o̲
      b̲e̲g̲i̲n̲
         c := (1 + 2 × i - X) × b - (i⭡2) × a;
         a := b;
         b := c
      e̲n̲d̲;
   La := c
e̲n̲d̲;