A036976 Becomes a prime if a 1 is inserted before each digit.

1, 3, 7, 9, 17, 23, 27, 39, 51, 63, 69, 81, 93, 119, 121, 127, 137, 161, 193, 199, 203, 209, 233, 271, 301, 311, 313, 323, 331, 337, 343, 359, 361, 367, 371, 373, 431, 439, 443, 451, 463, 469, 479, 481, 497, 503, 523, 557, 577, 583, 587, 607, 641, 661, 677