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 | 1 |
| 1 | 0 |
| 2 | 200 |
| 3 | 0 |
| 4 | 6800 |
| 5 | 512 |
| 6 | 103000 |
| 7 | 28160 |
| 8 | 935200 |
| 9 | 366080 |
| 10 | 5805032 |
| 11 | 2562560 |
| 12 | 27135920 |
| 13 | 12446720 |
| 14 | 102442360 |
| 15 | 47297536 |
| 16 | 328075840 |
| 17 | 150492160 |
| 18 | 922953480 |
| 19 | 418401280 |
| 20 | 2339194064 |
| 21 | 1046003200 |
| 22 | 5442091160 |
| 23 | 2399654400 |
| 24 | 11788144480 |
| 25 | 5127682560 |
| 26 | 24036948520 |
| 27 | 10321958400 |