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 | 11 |
| 3 | 44 |
| 4 | 189 |
| 5 | 880 |
| 6 | 4542 |
| 7 | 26712 |
| 8 | 182793 |
| 9 | 1461368 |
| 10 | 13477650 |
| 11 | 140564536 |
| 12 | 1627370146 |
| 13 | 20621925504 |
| 14 | 283161372284 |
| 15 | 4182215376240 |
| 16 | 66065933347425 |
| 17 | 1111053154779720 |
| 18 | 19814069772086730 |
| 19 | 373435157945506680 |
| 20 | 7415765258637418950 |
| 21 | 154751460071567005920 |
| 22 | 3385387828167428482020 |