A274633 Main diagonal of array in A274630.
1, 5, 9, 6, 4, 14, 2, 19, 11, 3, 20, 15, 8, 10, 25, 22, 33, 27, 7, 28, 43, 29, 36, 17, 12, 13, 16, 62, 18, 40, 66, 35, 71, 59, 77, 74, 50, 45, 49, 85, 60, 21, 24, 58, 23, 99, 30, 78, 32, 31, 67, 103, 110, 37, 42, 34, 26, 38, 73, 83, 80, 39, 134, 47, 79, 105, 41, 95, 148, 106, 150, 102, 44, 92
Offset: 1