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 | 63 |
| 2 | 448 |
| 3 | 2816 |
| 4 | 16896 |
| 5 | 99200 |
| 6 | 575872 |
| 7 | 3322112 |
| 8 | 19096064 |
| 9 | 109541824 |
| 10 | 627653440 |
| 11 | 3594256896 |
| 12 | 20577979392 |
| 13 | 117814911744 |
| 14 | 674630384384 |
| 15 | 3864033226240 |
| 16 | 22138650598400 |
| 17 | 126885674577728 |
| 18 | 727501822004416 |
| 19 | 4172725286118656 |