Euler2.clj

;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.
;*** PROBLEM WITH EULER CONDITION THEY SAY 4 MILLION BUT ACTUALLY MEAN 40 MILLION

(defn fibr-sum-even[upto]
    (loop [a 0N b 1N sum 0N]
    (println (str b " - "  sum))
    
    (if (> b upto) sum
      (if (= (mod b 2) 0) 
        (recur b (+ a b) (+ sum b))
        (recur b (+ a b)  sum )))))

(fibr-sum-even 4000000N)