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 | 3 |
| 3 | 19 |
| 4 | 207 |
| 5 | 3451 |
| 6 | 81663 |
| 7 | 2602699 |
| 8 | 107477247 |
| 9 | 5581680571 |
| 10 | 356046745023 |
| 11 | 27365431508779 |
| 12 | 2494237642655487 |
| 13 | 266005087863259291 |
| 14 | 32815976815540917183 |
| 15 | 4636895313201764853259 |
| 16 | 743988605732990946684927 |