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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 18 |
| 6 | 61 |
| 7 | 210 |
| 8 | 778 |
| 9 | 3008 |
| 10 | 12219 |
| 11 | 52268 |
| 12 | 231726 |
| 13 | 1083012 |
| 14 | 5202199 |
| 15 | 26307710 |
| 16 | 135972580 |
| 17 | 738339310 |
| 18 | 4081523615 |
| 19 | 23649300862 |
| 20 | 139096468520 |
| 21 | 855529383396 |
| 22 | 5329630673249 |
| 23 | 34643027568520 |
| 24 | 227682351175868 |
| 25 | 1558106351450416 |
| 26 | 10766192988109009 |