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 | 2 |
| 2 | 12 |
| 3 | 72 |
| 4 | 432 |
| 5 | 2592 |
| 6 | 15552 |
| 7 | 93312 |
| 8 | 559872 |
| 9 | 3359232 |
| 10 | 20155392 |
| 11 | 120932352 |
| 12 | 725594112 |
| 13 | 4353564672 |
| 14 | 26121388032 |
| 15 | 156728328192 |
| 16 | 940369969152 |
| 17 | 5642219814912 |
| 18 | 33853318889472 |
| 19 | 203119913336832 |
| 20 | 1218719480020992 |
| 21 | 7312316880125952 |
| 22 | 43873901280755712 |
| 23 | 263243407684534272 |