A080331 Index in A002858 of the larger of the two Ulam numbers that sum to the n-th Ulam number.

0, 0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 13, 15, 15, 17, 13, 17, 20, 20, 20, 20, 20, 25, 26, 27, 28, 20, 20, 27, 25, 33, 27, 28, 36, 37, 38, 27, 40, 38, 42, 42, 44, 40, 46, 47, 48, 42, 40, 51, 52, 38, 53, 44, 56, 56, 54, 59, 55, 61, 56, 53, 61, 65, 65, 67, 61, 69, 70