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 | 10 |
| 2 | 120 |
| 3 | 1320 |
| 4 | 14630 |
| 5 | 160920 |
| 6 | 1771440 |
| 7 | 19485720 |
| 8 | 214357440 |
| 9 | 2357931730 |
| 10 | 25937408640 |
| 11 | 285311493720 |
| 12 | 3138428201160 |
| 13 | 34522710196920 |
| 14 | 379749831637440 |
| 15 | 4177248147997440 |
| 16 | 45949729842155150 |
| 17 | 505447028263532520 |
| 18 | 5559917313256631160 |
| 19 | 61159090445821012920 |