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+;;;; copyright 2016 rsiddharth <s@ricketyspace.net>
+;;;; under gnu general public license version 3 or higher.
+
+(define-module (net ricketyspace taocp utils math)
+  #:use-module (srfi srfi-1)
+  #:export (compute-exp1-n
+            fib
+            fib-range))
+
+(define (compute-exp1-n fx n)
+  "Evaluate function FX for `x` equals 1 to N and return all results
+as a list
+
+Expression FX is a function that takes exactly one arugment.
+
+For instance `(lambda (x) (* x x))` is a valid FX.
+"
+  (cond ((= n 0) '())
+        (else (cons (fx n) (compute-exp1-n fx (1- n))))))
+
+(define (fib n)
+  "Returns Fibonacci of N.
+
+This function is useless for large values of N. Use `fib-fast`
+function defined in (taocp one two eight fib).
+"
+  (cond ((= n 0) 0)
+        ((= n 1) 1)
+        (else (+ (fib (- n 1)) (fib (- n 2))))))
+
+(define (fib-range start end)
+  "Returns Fibonacci sequence between START and END.
+
+This function is useless wher START/END is large. Use `fib-fast-range`
+function defined in (taocp one two eight fib).
+"
+  (let ((f (lambda (x) (cons x (fib x))))
+        (count (1+ (- end start ))))
+  (map f (iota count start))))