1 files changed, 24 insertions, 0 deletions
diff --git a/challenge-246/roger-bell-west/python/ch-2.py b/challenge-246/roger-bell-west/python/ch-2.py
new file mode 100755
index 0000000000..aca37cd440
--- /dev/null
+++ b/challenge-246/roger-bell-west/python/ch-2.py
@@ -0,0 +1,24 @@
+#! /usr/bin/python3
+
+def linearrecurrencesecondorder(seq):
+  a = seq[0:3]
+  b = seq[1:4]
+  c = seq[2:5]
+  q = (b[2] * a[0] - b[0] * a[2]) // (b[1] * a[0] - b[0] * a[1])
+  p = (a[2] - a[1] * q) // a[0]
+  return p * a[0] + q * a[1] == a[2] and p * b[0] + q * b[1] == b[2] and p * c[0] + q * c[1] == c[2]
+
+import unittest
+
+class TestLinearrecurrencesecondorder(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(linearrecurrencesecondorder([1, 1, 2, 3, 5]), True, 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(linearrecurrencesecondorder([4, 2, 4, 5, 7]), False, 'example 2')
+
+  def test_ex3(self):
+    self.assertEqual(linearrecurrencesecondorder([4, 1, 2, -3, 8]), True, 'example 3')
+
+unittest.main()