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 | 6 |
| 3 | 24 |
| 4 | 92 |
| 5 | 360 |
| 6 | 1448 |
| 7 | 5888 |
| 8 | 24144 |
| 9 | 99744 |
| 10 | 414432 |
| 11 | 1729920 |
| 12 | 7249088 |
| 13 | 30476416 |
| 14 | 128487552 |
| 15 | 543014912 |
| 16 | 2299764992 |
| 17 | 9758138880 |
| 18 | 41473582592 |
| 19 | 176530905088 |
| 20 | 752401603584 |
| 21 | 3210723420160 |
| 22 | 13716154361856 |
| 23 | 58653842276352 |
| 24 | 251049168687104 |
| 25 | 1075442759868416 |