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 | 96 |
| 2 | 2808 |
| 3 | 43680 |
| 4 | 450450 |
| 5 | 3459456 |
| 6 | 21237216 |
| 7 | 109219968 |
| 8 | 486370170 |
| 9 | 1921462400 |
| 10 | 6859620768 |
| 11 | 22449667968 |
| 12 | 68128506264 |
| 13 | 193501082880 |
| 14 | 518306472000 |
| 15 | 1317650231040 |
| 16 | 3196331224515 |
| 17 | 7432299594720 |
| 18 | 16630917303000 |
| 19 | 35933837940000 |
| 20 | 75191555889450 |
| 21 | 152770145299200 |