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) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 31 |
| 4 | 129 |
| 5 | 531 |
| 6 | 2129 |
| 7 | 8351 |
| 8 | 32177 |
| 9 | 122211 |
| 10 | 458801 |
| 11 | 1706015 |
| 12 | 6293169 |
| 13 | 23057651 |
| 14 | 83992313 |
| 15 | 304424639 |
| 16 | 1098525761 |
| 17 | 3948727555 |
| 18 | 14145206209 |
| 19 | 50515602111 |
| 20 | 179904080257 |
| 21 | 639103899411 |
| 22 | 2265253438745 |
| 23 | 8012421964063 |