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 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 11 |
| 6 | 26 |
| 7 | 71 |
| 8 | 200 |
| 9 | 602 |
| 10 | 1904 |
| 11 | 6317 |
| 12 | 21886 |
| 13 | 78911 |
| 14 | 295259 |
| 15 | 1143535 |
| 16 | 4574143 |
| 17 | 18859677 |
| 18 | 80014834 |
| 19 | 348776576 |
| 20 | 1559776268 |
| 21 | 7147792818 |
| 22 | 33526120082 |
| 23 | 160785623545 |
| 24 | 787685471322 |
| 25 | 3938427356614 |
| 26 | 20082117944245 |
| 27 | 104349745809073 |
| 28 | 552166953567228 |