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 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 13 |
| 6 | 356 |
| 7 | 3126 |
| 8 | 28691 |
| 9 | 70268 |
| 10 | 271396 |
| 11 | 6534495 |
| 12 | 64591632 |
| 13 | 162057126 |
| 14 | 26237436541 |
| 15 | 66438353080 |
| 16 | 7020479040553 |
| 17 | 11201604625686 |
| 18 | 296414282891996 |
| 19 | 32360305554728271 |
| 20 | 339791857819043616 |
| 21 | 871053578019254406 |
| 22 | 5731478440138170841 |
| 23 | 9181907843495831675 |