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) |
|---|---|
| 2 | 1 |
| 3 | 0 |
| 4 | 6 |
| 5 | 10 |
| 6 | 60 |
| 7 | 231 |
| 8 | 1148 |
| 9 | 5832 |
| 10 | 32175 |
| 11 | 188375 |
| 12 | 1169652 |
| 13 | 7663734 |
| 14 | 52808847 |
| 15 | 381494400 |
| 16 | 2881338840 |
| 17 | 22696790440 |
| 18 | 186058768140 |
| 19 | 1584156272157 |
| 20 | 13984151627030 |
| 21 | 127779961705620 |
| 22 | 1206805491491985 |
| 23 | 11764472685724561 |
| 24 | 118230099056654664 |