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 | 10 |
| 2 | 1080 |
| 3 | 59340 |
| 4 | 1049680 |
| 5 | 9768870 |
| 6 | 60474120 |
| 7 | 282492280 |
| 8 | 1073774880 |
| 9 | 3486843810 |
| 10 | 10000100440 |
| 11 | 25937586180 |
| 12 | 61917613680 |
| 13 | 137858863870 |
| 14 | 289255193640 |
| 15 | 576651150960 |
| 16 | 1099512677440 |
| 17 | 2015995321530 |
| 18 | 3570469117560 |
| 19 | 6131068735420 |
| 20 | 10240003201680 |
| 21 | 16679885064150 |