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 | 4 |
| 5 | 31 |
| 6 | 146 |
| 7 | 1289 |
| 8 | 7736 |
| 9 | 85831 |
| 10 | 641302 |
| 11 | 8732989 |
| 12 | 78432212 |
| 13 | 1270475155 |
| 14 | 13338831858 |
| 15 | 250740220345 |
| 16 | 3013809363056 |
| 17 | 64512904742895 |
| 18 | 873589792390382 |
| 19 | 20982459271174517 |
| 20 | 316070362138732172 |
| 21 | 8418423492219771211 |
| 22 | 139628838506569935338 |
| 23 | 4084524856346911809777 |