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 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 16 |
| 4 | 45 |
| 5 | 121 |
| 6 | 320 |
| 7 | 841 |
| 8 | 2205 |
| 9 | 5776 |
| 10 | 15125 |
| 11 | 39601 |
| 12 | 103680 |
| 13 | 271441 |
| 14 | 710645 |
| 15 | 1860496 |
| 16 | 4870845 |
| 17 | 12752041 |
| 18 | 33385280 |
| 19 | 87403801 |
| 20 | 228826125 |
| 21 | 599074576 |
| 22 | 1568397605 |
| 23 | 4106118241 |
| 24 | 10749957120 |
| 25 | 28143753121 |
| 26 | 73681302245 |
| 27 | 192900153616 |
| 28 | 505019158605 |
| 29 | 1322157322201 |