finding e to nth digit

Author: microice333

n_digit_e.py

@@ -0,0 +1,28 @@
+# find e to nth digit by brothers' formulae: http://www.intmath.com/exponential-logarithmic-functions/calculating-e.php
+import decimal
+
+
+def factorial(n):
+    factorials = [1]
+    for i in range(1, n + 1):
+        factorials.append(factorials[i - 1] * i)
+    return factorials
+
+
+def compute_e(n):
+    decimal.getcontext().prec = n + 1
+    e = 2
+    factorials = factorial(2 * n + 1)
+    for i in range(1, n + 1):
+        counter = 2 * i + 2
+        denominator = factorials[2 * i + 1]
+        e += decimal.Decimal(counter / denominator)
+    return e
+
+
+while True:
+    n = int(input("Please type number between 0-1000"))
+    if n >= 0 and n <= 1000:
+        break
+
+print(str(compute_e(n))[:n + 1])