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) |
|---|---|
| 1 | 1 |
| 2 | 18 |
| 3 | 246 |
| 4 | 3016 |
| 5 | 34920 |
| 6 | 390480 |
| 7 | 4266640 |
| 8 | 45866880 |
| 9 | 487198080 |
| 10 | 5128019200 |
| 11 | 53591788800 |
| 12 | 556898534400 |
| 13 | 5760319052800 |
| 14 | 59355533260800 |
| 15 | 609667001088000 |
| 16 | 6245327982592000 |
| 17 | 63829424295936000 |
| 18 | 651070362673152000 |
| 19 | 6629663109210112000 |
| 20 | 67406737815797760000 |