77 = 4² + 5² + 6²

Certain integers have the property that they can be partitioned into distinct positive integers whose reciprocals sum to 1

Example 11 = 2 + 3 + 6 and 1/2 + 1/3 + 1 / 6 = 1. All integers exceeding 77 possess this property

R. L. Graham, Journal of the Australian Mathematical Society (1963), 3:435-441 Cambridge University Press