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 | 1 |
| 4 | 6 |
| 5 | 35 |
| 6 | 221 |
| 7 | 1554 |
| 8 | 12108 |
| 9 | 104293 |
| 10 | 986452 |
| 11 | 10186669 |
| 12 | 114173261 |
| 13 | 1381606490 |
| 14 | 17963133122 |
| 15 | 249838334627 |
| 16 | 3702507093782 |
| 17 | 58255992451047 |
| 18 | 970036965428901 |
| 19 | 17043762930794782 |
| 20 | 315148172259643152 |
| 21 | 6117607922562556061 |
| 22 | 124394868793682972996 |