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 | 1 |
| 2 | 515 |
| 3 | 21225 |
| 4 | 324275 |
| 5 | 2862790 |
| 6 | 17714466 |
| 7 | 85232910 |
| 8 | 339635850 |
| 9 | 1168343775 |
| 10 | 3571356685 |
| 11 | 9906622271 |
| 12 | 25333920885 |
| 13 | 60457751900 |
| 14 | 135939162100 |
| 15 | 290221510860 |
| 16 | 592024274916 |
| 17 | 1159935330765 |
| 18 | 2192313968775 |
| 19 | 4011847886725 |
| 20 | 7130537084615 |