A067942 Let rep(n) be the n-th repunit number; sequence gives values of n such that rep(n) == rep(9) (mod n).

1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 15, 16, 18, 20, 21, 24, 25, 30, 32, 33, 36, 39, 40, 45, 48, 50, 55, 60, 63, 64, 72, 73, 75, 80, 90, 96, 99, 100, 101, 105, 111, 117, 120, 125, 128, 137, 144, 150, 153, 160, 164, 165, 171, 180, 192, 195, 200, 207, 222, 225, 231, 240