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 | 0 |
| 2 | 3 |
| 3 | 3 |
| 4 | 21 |
| 5 | 86 |
| 6 | 410 |
| 7 | 1874 |
| 8 | 8840 |
| 9 | 41755 |
| 10 | 197883 |
| 11 | 936625 |
| 12 | 4434387 |
| 13 | 20996674 |
| 14 | 99434998 |
| 15 | 470911050 |
| 16 | 2230166446 |
| 17 | 10561720749 |
| 18 | 50018822099 |
| 19 | 236882697591 |
| 20 | 1121846953883 |
| 21 | 5312927519916 |
| 22 | 25161362888858 |
| 23 | 119161085234850 |
| 24 | 564332106834338 |