1 files changed, 7 insertions, 0 deletions
diff --git a/progs/a663.py b/progs/a663.py
new file mode 100644
index 0000000..7130b51
--- /dev/null
+++ b/progs/a663.py
@@ -0,0 +1,7 @@
+def count_binary_seq(n): 
+	nCr = 1
+	res = 1
+	for r in range(1, n + 1): 
+		nCr = (nCr * (n + 1 - r)) / r 
+		res += nCr * nCr 
+	return res 
+\ No newline at end of file