の形をしている素数.| 3 | 5 | 17 | 257 | 65537 |
| 3 | = 220 + 1 | prime number |
| 5 | = 221 + 1 | prime number |
| 17 | = 222 + 1 | prime number |
| 257 | = 223 + 1 | prime number |
| 65537 | = 224 + 1 | prime number |
| 4294967297 | = 225 + 1 | = 641 * 6700417 |
| 18446744073709551617 | = 226 + 1 | = 274177 * 67280421310721 |
| 340282366920938463463374607431768211457 | = 227 + 1 | = 59649589127497217 * 5704689200685129054721 |