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 | 5 |
| 3 | 43 |
| 4 | 513 |
| 5 | 7781 |
| 6 | 142861 |
| 7 | 3075255 |
| 8 | 75879553 |
| 9 | 2110145833 |
| 10 | 65275127541 |
| 11 | 2222656864451 |
| 12 | 82595058938305 |
| 13 | 3325666654250253 |
| 14 | 144214230714973693 |
| 15 | 6700048267934377231 |
| 16 | 331988586859256529921 |
| 17 | 17475202293073669341905 |
| 18 | 973765103770578798536293 |