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 | 97 |
| 4 | 1249 |
| 5 | 19041 |
| 6 | 338281 |
| 7 | 6872929 |
| 8 | 156878337 |
| 9 | 3964344769 |
| 10 | 109649487241 |
| 11 | 3290138609121 |
| 12 | 106344130171489 |
| 13 | 3680908100971297 |
| 14 | 135759417307847529 |
| 15 | 5312294503297893601 |
| 16 | 219710817062641086721 |
| 17 | 9572694339517999983489 |
| 18 | 438078249108592685152777 |