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 | 2 |
| 2 | 20 |
| 3 | 272 |
| 4 | 3440 |
| 5 | 40952 |
| 6 | 468560 |
| 7 | 5217032 |
| 8 | 56953280 |
| 9 | 612579512 |
| 10 | 6513215600 |
| 11 | 68618940392 |
| 12 | 717570463520 |
| 13 | 7458134171672 |
| 14 | 77123207545040 |
| 15 | 794108867905352 |
| 16 | 8146979811148160 |
| 17 | 83322818300333432 |
| 18 | 849905364703000880 |