A137760 Distinct numbers in writing first numerator and then denominator (left to right) of Leibniz's harmonic-like triangle.
1, 2, 3, 5, 6, 4, 7, 12, 9, 20, 31, 30, 11, 49, 60, 13, 42, 71, 105, 209, 140, 8, 15, 56, 97, 168, 351, 280, 17, 72, 127, 252, 545, 504, 1471, 630, 10, 19, 90, 161, 360, 799, 840, 2561, 1260, 21, 110, 199, 495, 1121, 1320, 4159, 2310, 10625, 2772
Offset: 1
Examples
1/1; --> 1 1/2, 1/2; --> 2 1/3, 5/6, 1/3; --> 3 5 6 1/4, 7/12, 7/12, 1/4; --> ... 1/5, 9/20, 31/30, 9/20, 1/5;