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 | 8 |
| 3 | 46 |
| 4 | 352 |
| 5 | 3378 |
| 6 | 38912 |
| 7 | 522702 |
| 8 | 8024064 |
| 9 | 138586722 |
| 10 | 2659565568 |
| 11 | 56141737518 |
| 12 | 1292851544064 |
| 13 | 32253357421842 |
| 14 | 866534937329664 |
| 15 | 24943658876605902 |
| 16 | 765883864848531456 |
| 17 | 24985882009464388290 |
| 18 | 863077992845681885184 |
| 19 | 31469256501815056673070 |