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 | 4 |
| 2 | 24 |
| 3 | 104 |
| 4 | 384 |
| 5 | 1284 |
| 6 | 4012 |
| 7 | 11924 |
| 8 | 34100 |
| 9 | 94584 |
| 10 | 255852 |
| 11 | 677850 |
| 12 | 1764482 |
| 13 | 4523924 |
| 14 | 11447870 |
| 15 | 28636218 |
| 16 | 70907326 |
| 17 | 173991368 |
| 18 | 423469988 |
| 19 | 1023162920 |
| 20 | 2455645268 |
| 21 | 5858183260 |
| 22 | 13898041838 |
| 23 | 32804047708 |
| 24 | 77067740230 |