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 | 3 |
| 2 | 22 |
| 3 | 230 |
| 4 | 3048 |
| 5 | 48152 |
| 6 | 875536 |
| 7 | 17907024 |
| 8 | 405320320 |
| 9 | 10030449536 |
| 10 | 268836428544 |
| 11 | 7744939895552 |
| 12 | 238352004594688 |
| 13 | 7795463142466560 |
| 14 | 269761049981827072 |
| 15 | 9839883848966985728 |
| 16 | 377091995258812268544 |
| 17 | 15139047281589466136576 |
| 18 | 635088889901946682408960 |
| 19 | 27775758544209632635060224 |
| 20 | 1263876454164193257295446016 |