(LETREC FIRSTSUMS
  (FIRSTSUMS LAMBDA (K)
    (FIRST K (SUMS (QUOTE 0) (INTEGERSFROM (QUOTE 1)))))
  (FIRST LAMBDA (K X)
    (IF (EQ K (QUOTE 0)) (QUOTE NIL)
        (CONS (CAR X) (FIRST (SUB K (QUOTE 1)) (FORCE (CDR X))))))
  (SUMS LAMBDA (A X)
     (LET (CONS Y (DELAY (SUMS Y (FORCE (CDR X)))))
		(Y ADD A (CAR X))))
  (INTEGERSFROM LAMBDA (M)
    (CONS M (DELAY (INTEGERSFROM (ADD M (QUOTE 1))))))) &