A066200 a(1) = 1; for n > 1, a(n) = a(n-1)-(n+2) if this is positive and has not already appeared, otherwise a(n) = a(n-1)+(n+2).

1, 5, 10, 4, 11, 3, 12, 2, 13, 25, 38, 24, 9, 25, 8, 26, 7, 27, 6, 28, 51, 75, 50, 76, 49, 21, 50, 20, 51, 19, 52, 18, 53, 17, 54, 16, 55, 15, 56, 14, 57, 101, 146, 100, 147, 99, 148, 98, 47, 99, 46, 100, 45, 101, 44, 102, 43, 103, 42, 104, 41, 105, 40, 106, 39, 107, 176