>>> from triangulars import triangulars

>>> triangulars (10)
[(1, 1), (3, 2), (6, 3), (10, 4)]
>>> triangulars (50)
[(1, 1), (3, 2), (6, 3), (10, 4), (15, 5), (21, 6), (28, 7), (36, 8), (45, 9)]