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 | 0 |
| 1 | 1 |
| 2 | 6 |
| 3 | 36 |
| 4 | 216 |
| 5 | 1304 |
| 6 | 7920 |
| 7 | 48320 |
| 8 | 295680 |
| 9 | 1812672 |
| 10 | 11124864 |
| 11 | 68320000 |
| 12 | 419719680 |
| 13 | 2579051008 |
| 14 | 15849305088 |
| 15 | 97406521344 |
| 16 | 598661038080 |
| 17 | 3679444570112 |
| 18 | 22614556631040 |
| 19 | 138994100486144 |
| 20 | 854291341737984 |
| 21 | 5250689954316288 |
| 22 | 32272093691707392 |
| 23 | 198352703517884416 |