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 | 1 |
| 2 | 144 |
| 3 | 3402 |
| 4 | 33280 |
| 5 | 196875 |
| 6 | 843696 |
| 7 | 2890804 |
| 8 | 8404992 |
| 9 | 21552885 |
| 10 | 50050000 |
| 11 | 107259966 |
| 12 | 215115264 |
| 13 | 408051007 |
| 14 | 738163440 |
| 15 | 1281825000 |
| 16 | 2148007936 |
| 17 | 3488588649 |
| 18 | 5510925072 |
| 19 | 8493019570 |
| 20 | 12801600000 |
| 21 | 18913471731 |
| 22 | 27440513584 |