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 | 45 |
| 3 | 378 |
| 4 | 3402 |
| 5 | 32076 |
| 6 | 312741 |
| 7 | 3127410 |
| 8 | 31899582 |
| 9 | 330595668 |
| 10 | 3471254514 |
| 11 | 36848701764 |
| 12 | 394807518900 |
| 13 | 4263921204120 |
| 14 | 46370143094805 |
| 15 | 507343918566690 |
| 16 | 5580783104233590 |
| 17 | 61682339573108100 |
| 18 | 684673969261499910 |
| 19 | 7629224228913856140 |
| 20 | 85308598196036755020 |