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 | 6 |
| 2 | 60 |
| 3 | 744 |
| 4 | 10224 |
| 5 | 148896 |
| 6 | 2250816 |
| 7 | 34922880 |
| 8 | 552386304 |
| 9 | 8867756544 |
| 10 | 144044098560 |
| 11 | 2362292213760 |
| 12 | 39049785446400 |
| 13 | 649843233546240 |
| 14 | 10876273137008640 |
| 15 | 182934715370471424 |
| 16 | 3090181365862170624 |
| 17 | 52398620697685524480 |
| 18 | 891492911924665122816 |
| 19 | 15213249205591283859456 |
| 20 | 260315328935885892747264 |