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 | 12 |
| 3 | 60 |
| 4 | 420 |
| 5 | 4620 |
| 6 | 360 |
| 7 | 1021020 |
| 8 | 19399380 |
| 9 | 446185740 |
| 10 | 13860 |
| 11 | 401120980260 |
| 12 | 2520 |
| 13 | 608500527054420 |
| 14 | 26165522663340060 |
| 15 | 180180 |
| 16 | 65178316954380089460 |
| 17 | 3845520700308425278140 |
| 18 | 234576762718813941966540 |
| 19 | 15716643102160534111758180 |
| 20 | 27720 |
| 21 | 3063060 |
| 22 | 6435289534681345815798169108260 |