#! /usr/bin/python3 import unittest from math import sqrt,floor,log from collections import deque def isprime(candidate): if candidate < 2: return False elif candidate==2: return True elif candidate==3: return True elif candidate % 2 == 0: return False elif candidate % 3 == 0: return False anchor = 0 limit = int(sqrt(candidate)) while True: anchor += 6 for t in range(anchor-1,anchor+2,2): if t > limit: return True if candidate % t == 0: return False def perrinprime(n): out = set() seq = deque([3, 0, 2]) while True: nv = seq[0] + seq[1] seq.popleft() seq.append(nv) if isprime(nv): out.add(nv) if len(out) >= n: break o = list(out) o.sort() return o class TestPerrinprime(unittest.TestCase): def test_ex1(self): self.assertEqual(perrinprime(13), [2, 3, 5, 7, 17, 29, 277, 367, 853, 14197, 43721, 1442968193, 792606555396977],'example 1') unittest.main()