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 | 2 |
| 3 | 9 |
| 4 | 44 |
| 5 | 230 |
| 6 | 1236 |
| 7 | 6790 |
| 8 | 37832 |
| 9 | 213057 |
| 10 | 1209660 |
| 11 | 6912367 |
| 12 | 39705516 |
| 13 | 229055918 |
| 14 | 1326168018 |
| 15 | 7701734250 |
| 16 | 44846271632 |
| 17 | 261735599172 |
| 18 | 1530650010312 |
| 19 | 8967361033572 |
| 20 | 52619233554120 |
| 21 | 309203221308702 |
| 22 | 1819290987055630 |
| 23 | 10716835948503349 |
| 24 | 63196331969007264 |