78 forms a Ruth–Aaron pair with 77. A Ruth–Aaron pair consists of two consecutive integers (e.g., 714 and 715) for which the sums of the prime factors of each integer are equal:
714 = 2 × 3 × 7 × 17
and
715 = 5 × 11 × 13
-and-
2 + 3 + 7 + 17 = 5 + 11 + 13 = 29.