A050716 Inserting a digit '6' between adjacent digits of n makes a prime.

13, 17, 23, 29, 37, 41, 43, 47, 53, 59, 61, 71, 79, 83, 97, 101, 103, 107, 109, 127, 131, 133, 139, 151, 157, 161, 173, 193, 211, 221, 223, 227, 251, 269, 281, 283, 301, 307, 311, 323, 329, 347, 349, 353, 371, 377, 401, 421, 457, 463, 479, 481, 487, 517, 523