A264989 Self-inverse permutation of nonnegative integers: a(n) = (A264987(n)-1) / 2.
0, 1, 2, 5, 4, 3, 6, 7, 11, 14, 16, 8, 17, 13, 9, 18, 10, 12, 15, 19, 20, 47, 22, 29, 56, 34, 38, 41, 43, 23, 50, 49, 32, 59, 25, 35, 44, 52, 26, 53, 40, 27, 54, 28, 36, 45, 55, 21, 48, 31, 30, 57, 37, 39, 42, 46, 24, 51, 58, 33, 60, 61, 101, 128, 142, 74, 155, 67, 83, 164, 88, 110, 137, 169, 65, 146, 103, 92, 173, 115, 119, 122
Offset: 0