A032706 n prefixed by '6' and followed by '1' is a prime.

0, 3, 4, 6, 9, 10, 12, 13, 15, 21, 22, 27, 30, 31, 36, 42, 45, 48, 49, 52, 55, 57, 58, 66, 69, 70, 76, 78, 79, 84, 87, 91, 96, 97, 99, 100, 103, 105, 109, 112, 114, 115, 121, 123, 126, 129, 133, 138, 144, 147, 151, 156, 163, 165, 168, 175, 178, 186, 187, 196