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 | 18 |
| 3 | 504 |
| 4 | 5200 |
| 5 | 31500 |
| 6 | 136710 |
| 7 | 471968 |
| 8 | 1378944 |
| 9 | 3547800 |
| 10 | 8258250 |
| 11 | 17728920 |
| 12 | 35603568 |
| 13 | 67606084 |
| 14 | 122399550 |
| 15 | 212688000 |
| 16 | 356602880 |
| 17 | 579419568 |
| 18 | 915652674 |
| 19 | 1411582200 |
| 20 | 2128266000 |
| 21 | 3145097340 |
| 22 | 4563969718 |
| 23 | 6514114464 |
| 24 | 9157680000 |
| 25 | 12696125000 |
| 26 | 17377501050 |