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 | 0 |
| 2 | 2 |
| 3 | 8 |
| 4 | 36 |
| 5 | 184 |
| 6 | 1110 |
| 7 | 7776 |
| 8 | 62216 |
| 9 | 559952 |
| 10 | 5599530 |
| 11 | 61594840 |
| 12 | 739138092 |
| 13 | 9608795208 |
| 14 | 134523132926 |
| 15 | 2017846993904 |
| 16 | 32285551902480 |
| 17 | 548854382342176 |
| 18 | 9879378882159186 |
| 19 | 187708198761024552 |
| 20 | 3754163975220491060 |
| 21 | 78837443479630312280 |
| 22 | 1734423756551866870182 |