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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 112 |
| 5 | 3368 |
| 6 | 39680 |
| 7 | 282248 |
| 8 | 1444928 |
| 9 | 5865552 |
| 10 | 20014112 |
| 11 | 59673360 |
| 12 | 159698416 |
| 13 | 391202680 |
| 14 | 890095584 |
| 15 | 1902427800 |
| 16 | 3853570560 |
| 17 | 7450556064 |
| 18 | 13829016768 |
| 19 | 24759442464 |
| 20 | 42930138864 |
| 21 | 72328779720 |
| 22 | 118747638592 |