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) |
|---|---|
| 6 | 1 |
| 7 | 63 |
| 8 | 2842 |
| 9 | 116172 |
| 10 | 4654713 |
| 11 | 189142107 |
| 12 | 7923937307 |
| 13 | 345104368752 |
| 14 | 15688849238062 |
| 15 | 745831503236820 |
| 16 | 37094603885430728 |
| 17 | 1929672890969261256 |
| 18 | 104918114960824458448 |
| 19 | 5956513043619244790970 |
| 20 | 352719666690509340493680 |
| 21 | 21759830035878816514854144 |