A076786 Squarefree numbers such that in decimal representation all their prefixes are also squarefree.

1, 2, 3, 5, 6, 7, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 26, 29, 30, 31, 33, 34, 35, 37, 38, 39, 51, 53, 55, 57, 58, 59, 61, 62, 65, 66, 67, 69, 70, 71, 73, 74, 77, 78, 79, 101, 102, 103, 105, 106, 107, 109, 110, 111, 113, 114, 115, 118, 119, 130, 131, 133, 134, 137