. 145 is the fourth number that is the sum of two different pairs of
squares. Also, 145 is the result of 34 + 43, making it a
Leyland number.
, making it a
factorion.[4] The only other numbers that have this property are
1,
2 and
40585.[4]
, making 145 the smallest number that can be written as the sum of a
square number and a factorial in 3 ways. The next number with this property is
46249.[5]