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 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 29 |
| 4 | 185 |
| 5 | 1257 |
| 6 | 8925 |
| 7 | 65445 |
| 8 | 491825 |
| 9 | 3768209 |
| 10 | 29324405 |
| 11 | 231153133 |
| 12 | 1841801065 |
| 13 | 14810069497 |
| 14 | 120029657805 |
| 15 | 979470140661 |
| 16 | 8040831465825 |
| 17 | 66361595715105 |
| 18 | 550284185213925 |
| 19 | 4582462506008253 |
| 20 | 38306388126997785 |