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 | 1 |
| 2 | 9 |
| 3 | 126 |
| 4 | 1920 |
| 5 | 27190 |
| 6 | 347168 |
| 7 | 3990467 |
| 8 | 42744527 |
| 9 | 440764556 |
| 10 | 4464045276 |
| 11 | 44863859589 |
| 12 | 449488519847 |
| 13 | 4498059105204 |
| 14 | 44992451829730 |
| 15 | 449969622539954 |
| 16 | 4499873022468708 |
| 17 | 44999449703306768 |
| 18 | 449997540235466340 |
| 19 | 4499988731927483569 |
| 20 | 44999947410278947807 |