Add new file

Twice_linear.py

+def dbl_linear(n):
+    list = [1]
+    y_pos = 0
+    z_pos = 0
+    while len(list) <= n:
+        y = 2 * list[y_pos] + 1
+        z = 3 * list[z_pos] + 1
+        if y > z:
+            list.append(z)
+            z_pos += 1
+        elif y < z:
+            list.append(y)
+            y_pos += 1
+        elif y == z:
+            list.append(y)
+            z_pos += 1
+            y_pos += 1
+    print(list[n])
+    return list[n]