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 | 3 |
| 3 | 6 |
| 4 | 49 |
| 5 | 147 |
| 6 | 2028 |
| 7 | 8112 |
| 8 | 159201 |
| 9 | 796005 |
| 10 | 20342448 |
| 11 | 122054688 |
| 12 | 3850078401 |
| 13 | 26950548807 |
| 14 | 1012487793408 |
| 15 | 8099902347264 |
| 16 | 353293863908769 |
| 17 | 3179644775178921 |
| 18 | 157973407966483200 |
| 19 | 1579734079664832000 |
| 20 | 88087149666575064369 |