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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 2 |
| 6 | 6 |
| 7 | 10 |
| 8 | 25 |
| 9 | 68 |
| 10 | 182 |
| 11 | 538 |
| 12 | 1748 |
| 13 | 5935 |
| 14 | 21585 |
| 15 | 82904 |
| 16 | 334037 |
| 17 | 1406934 |
| 18 | 6167455 |
| 19 | 28033776 |
| 20 | 131770437 |
| 21 | 638956188 |
| 22 | 3189940453 |
| 23 | 16369201031 |
| 24 | 86214798929 |
| 25 | 465480395911 |
| 26 | 2573390342437 |
| 27 | 14553415319929 |
| 28 | 84118459655982 |
| 29 | 496514424803358 |
| 30 | 2990633679878654 |