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 | 22 |
| 2 | 275 |
| 3 | 2530 |
| 4 | 18975 |
| 5 | 122430 |
| 6 | 702328 |
| 7 | 3661900 |
| 8 | 17627775 |
| 9 | 79264900 |
| 10 | 335937954 |
| 11 | 1351507830 |
| 12 | 5191041625 |
| 13 | 19125838600 |
| 14 | 67862904725 |
| 15 | 232671319474 |
| 16 | 773027485065 |
| 17 | 2494957906100 |
| 18 | 7839428942950 |
| 19 | 24025993453000 |
| 20 | 71941861591215 |