diff --git a/maths/hexagonal_number.py b/maths/hexagonal_number.py new file mode 100644 index 000000000000..28735c638f80 --- /dev/null +++ b/maths/hexagonal_number.py @@ -0,0 +1,48 @@ +""" +== Hexagonal Number == +The nth hexagonal number hn is the number of distinct dots +in a pattern of dots consisting of the outlines of regular +hexagons with sides up to n dots, when the hexagons are +overlaid so that they share one vertex. + +https://en.wikipedia.org/wiki/Hexagonal_number +""" + +# Author : Akshay Dubey (https://github.com/itsAkshayDubey) + + +def hexagonal(number: int) -> int: + """ + :param number: nth hexagonal number to calculate + :return: the nth hexagonal number + Note: A hexagonal number is only defined for positive integers + >>> hexagonal(4) + 28 + >>> hexagonal(11) + 231 + >>> hexagonal(22) + 946 + >>> hexagonal(0) + Traceback (most recent call last): + ... + ValueError: Input must be a positive integer + >>> hexagonal(-1) + Traceback (most recent call last): + ... + ValueError: Input must be a positive integer + >>> hexagonal(11.0) + Traceback (most recent call last): + ... + TypeError: Input value of [number=11.0] must be an integer + """ + if not isinstance(number, int): + raise TypeError(f"Input value of [number={number}] must be an integer") + if number < 1: + raise ValueError("Input must be a positive integer") + return number * (2 * number - 1) + + +if __name__ == "__main__": + import doctest + + doctest.testmod()