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 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 7 |
| 4 | 34 |
| 5 | 209 |
| 6 | 1260 |
| 7 | 8219 |
| 8 | 54677 |
| 9 | 374904 |
| 10 | 2617996 |
| 11 | 18588586 |
| 12 | 133708072 |
| 13 | 972484206 |
| 14 | 7139186644 |
| 15 | 52832157095 |
| 16 | 393700752053 |
| 17 | 2951755132720 |
| 18 | 22250074031893 |
| 19 | 168524281244364 |
| 20 | 1281906305775734 |
| 21 | 9788771511218660 |
| 22 | 75010092629043843 |
| 23 | 576625427728255451 |