Liebintzova řada
(define rada
(lambda (n suma cele_cis diference)
(cond
((< n 1) (* suma 4))
(else
(cond
((equal? (modulo cele_cis 2) 1)
(rada (- n 1) (- suma (/ 1 diference)) (+ cele_cis 1) (+ diference 2)))
(else (rada (- n 1) (+ suma (/ 1 diference)) (+ cele_cis 1) (+ diference 2))))))))
