A032702 Numbers k such that k prefixed by '2' and followed by '1' is prime.

1, 4, 5, 7, 8, 11, 13, 14, 16, 22, 25, 28, 31, 34, 35, 37, 38, 41, 44, 52, 53, 55, 59, 62, 67, 71, 73, 74, 79, 80, 85, 86, 97, 100, 101, 103, 106, 110, 112, 119, 121, 122, 134, 139, 140, 148, 149, 152, 160, 161, 166, 170, 175, 182, 184, 185, 187, 188, 191, 196

Offset: 1

Author

Patrick De Geest, May 15 1998

Keywords

• nonn
• base

Crossrefs

Cf. A032703-A032733.

Cf. A032682, A032683, A032684, A032685.

Extensions

Offset changed by Andrew Howroyd, Aug 11 2024