src/problems/002.lisp @ c19da8761e57

(defpackage :euler/002 #.euler:*use*)
(in-package :euler/002)

;; Each new term in the Fibonacci sequence is generated by adding the previous
;; two terms. By starting with 1 and 2, the first 10 terms will be:
;;
;;     1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
;;
;; By considering the terms in the Fibonacci sequence whose values do not exceed
;; four million, find the sum of the even-valued terms.

(define-problem (2 4613732)
  (iterate (for n :in-fibonacci t)
           (while (<= n 4000000))
           (when (evenp n)
             (summing n))))