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 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 10 |
| 7 | 29 |
| 8 | 90 |
| 9 | 295 |
| 10 | 1030 |
| 11 | 3838 |
| 12 | 15168 |
| 13 | 63117 |
| 14 | 275252 |
| 15 | 1254801 |
| 16 | 5968046 |
| 17 | 29551768 |
| 18 | 152005634 |
| 19 | 810518729 |
| 20 | 4472244574 |
| 21 | 25497104007 |
| 22 | 149993156234 |
| 23 | 909326652914 |
| 24 | 5674422994544 |
| 25 | 36408092349897 |
| 26 | 239942657880360 |