A032719 Numbers n such that n prefixed by '2' and followed by '7' is prime.

2, 5, 7, 13, 20, 23, 26, 28, 29, 34, 35, 37, 41, 43, 44, 46, 47, 55, 61, 64, 65, 67, 68, 70, 76, 77, 79, 83, 85, 88, 89, 91, 92, 95, 101, 106, 110, 115, 118, 122, 124, 127, 131, 134, 137, 139, 140, 146, 148, 151, 155, 157, 158, 161, 164, 172, 173, 175, 176