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) |
|---|---|
| 4 | 1 |
| 5 | 1 |
| 6 | 5 |
| 7 | 17 |
| 8 | 57 |
| 9 | 193 |
| 10 | 650 |
| 11 | 2173 |
| 12 | 7199 |
| 13 | 23619 |
| 14 | 76746 |
| 15 | 247103 |
| 16 | 788934 |
| 17 | 2499707 |
| 18 | 7866233 |
| 19 | 24603551 |
| 20 | 76538239 |
| 21 | 236960031 |
| 22 | 730506849 |
| 23 | 2243545795 |
| 24 | 6867375720 |
| 25 | 20958167581 |
| 26 | 63791696431 |
| 27 | 193708118293 |
| 28 | 586967142587 |
| 29 | 1775245686845 |