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 | 1 |
| 2 | 9 |
| 3 | 73 |
| 4 | 849 |
| 5 | 12241 |
| 6 | 211929 |
| 7 | 4280473 |
| 8 | 98806689 |
| 9 | 2565862561 |
| 10 | 74035143849 |
| 11 | 2349822967273 |
| 12 | 81361870604529 |
| 13 | 3051889548205681 |
| 14 | 123282485663042169 |
| 15 | 5335770920836028473 |
| 16 | 246332487897909570369 |
| 17 | 12083010395805261921601 |
| 18 | 627555570373369525058889 |
| 19 | 34404109751876393769480073 |