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 | 1 |
| 2 | 4 |
| 3 | 13 |
| 4 | 55 |
| 5 | 252 |
| 6 | 1242 |
| 7 | 6375 |
| 8 | 33885 |
| 9 | 184717 |
| 10 | 1028172 |
| 11 | 5820904 |
| 12 | 33427622 |
| 13 | 194299052 |
| 14 | 1141190188 |
| 15 | 6763576681 |
| 16 | 40405993509 |
| 17 | 243090678343 |
| 18 | 1471673620504 |
| 19 | 8959718123381 |
| 20 | 54824825183377 |
| 21 | 337018924981048 |
| 22 | 2080401423880834 |