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 | 65 |
| 3 | 425 |
| 4 | 2625 |
| 5 | 15625 |
| 6 | 90625 |
| 7 | 515625 |
| 8 | 2890625 |
| 9 | 16015625 |
| 10 | 87890625 |
| 11 | 478515625 |
| 12 | 2587890625 |
| 13 | 13916015625 |
| 14 | 74462890625 |
| 15 | 396728515625 |
| 16 | 2105712890625 |
| 17 | 11138916015625 |
| 18 | 58746337890625 |
| 19 | 308990478515625 |
| 20 | 1621246337890625 |