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 | 6 |
| 2 | 37 |
| 3 | 234 |
| 4 | 1512 |
| 5 | 9936 |
| 6 | 66096 |
| 7 | 443232 |
| 8 | 2985984 |
| 9 | 20155392 |
| 10 | 136048896 |
| 11 | 917070336 |
| 12 | 6167549952 |
| 13 | 41358864384 |
| 14 | 276451356672 |
| 15 | 1841557856256 |
| 16 | 12224809598976 |
| 17 | 80871817347072 |
| 18 | 533189772509184 |
| 19 | 3503818505060352 |
| 20 | 22952550207062016 |