This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 7 |
| 3 | 31 |
| 4 | 67 |
| 5 | 127 |
| 6 | 271 |
| 7 | 577 |
| 8 | 1087 |
| 9 | 2311 |
| 10 | 8191 |
| 11 | 78607 |
| 12 | 131071 |
| 13 | 524287 |
| 14 | 1114111 |
| 15 | 2367487 |
| 16 | 2672671 |
| 17 | 17825791 |
| 18 | 42762751 |
| 19 | 90870847 |
| 20 | 606076927 |
| 21 | 2147483647 |
| 22 | 5151653887 |
| 23 | 5815734271 |
| 24 | 9697230847 |
| 25 | 329705848831 |
| 26 | 474351505987 |
| 27 | 700624928767 |
| 28 | 892896952447 |
| 29 | 1168231104511 |
| 30 | 2482491097087 |