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 | 9 |
| 2 | 153 |
| 3 | 3177 |
| 4 | 73017 |
| 5 | 1785609 |
| 6 | 45543897 |
| 7 | 1197639081 |
| 8 | 32231934585 |
| 9 | 883404542025 |
| 10 | 24570973169433 |
| 11 | 691759954058985 |
| 12 | 19674867844155321 |
| 13 | 564462038150345097 |
| 14 | 16315646312285498457 |
| 15 | 474680922491822688297 |