name: legendre_value
input: 
  d:degree
  x: evaluation point
output:
  p: value of p(d,x)

  pm1 = 0
  p = 1

  LOOP from i = 1 to d

    pm2 <= pm1
    pm1 <= p
    p   <= ( ( 2 * i - 1 ) * x * pm1
          -  (     i - 1 ) *     pm2 )
          /  (     i     )