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) |
|---|---|
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 3 |
| 8 | 13 |
| 9 | 67 |
| 10 | 408 |
| 11 | 2874 |
| 12 | 23034 |
| 13 | 207185 |
| 14 | 2067928 |
| 15 | 22688218 |
| 16 | 271456443 |
| 17 | 3518003749 |
| 18 | 49097940464 |
| 19 | 734192914717 |
| 20 | 11711708730460 |
| 21 | 198519682344141 |
| 22 | 3563360442079351 |
| 23 | 67522465963443411 |
| 24 | 1346990675228935159 |
| 25 | 28217627569071978376 |
| 26 | 619338933079584448848 |