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 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 46 |
| 5 | 208 |
| 6 | 1002 |
| 7 | 5012 |
| 8 | 25863 |
| 9 | 136519 |
| 10 | 733902 |
| 11 | 4003475 |
| 12 | 22106155 |
| 13 | 123313289 |
| 14 | 693871975 |
| 15 | 3933700703 |
| 16 | 22447035938 |
| 17 | 128828019447 |
| 18 | 743142630614 |
| 19 | 4306327193744 |
| 20 | 25056121416684 |
| 21 | 146325789652514 |
| 22 | 857393585946194 |
| 23 | 5039223717251954 |
| 24 | 29700183601347111 |
| 25 | 175496470696059267 |