Euler Project 120

Let r be the remainder when (a1)ⁿ + (a+1)ⁿ is divided by a².

For example, if a = 7 and n = 3, then r = 42: 6³ + 8³ = 728  42 mod 49. And as n varies, so too will r, but for a = 7 it turns out that r_max = 42.

For 3  a  1000, find  r_max.

My Solution

(defun MaxReminder(a)

  (loop for i from 1 to (* 2 a) by 2

          maximize (rem (* 2 a i) (* a a))))

(defun Euler120(n)

  (loop for i from 3 to n

          sum (MaxReminder i)))