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) |
|---|---|
| 1 | 9 |
| 2 | 225 |
| 3 | 900 |
| 4 | 2025 |
| 5 | 22500 |
| 6 | 90000 |
| 7 | 202500 |
| 8 | 950625 |
| 9 | 2250000 |
| 10 | 9000000 |
| 11 | 20250000 |
| 12 | 85100625 |
| 13 | 95062500 |
| 14 | 225000000 |
| 15 | 900000000 |
| 16 | 2025000000 |
| 17 | 2487515625 |
| 18 | 8510062500 |
| 19 | 9506250000 |
| 20 | 18123890625 |
| 21 | 22500000000 |
| 22 | 90000000000 |
| 23 | 202500000000 |
| 24 | 248751562500 |
| 25 | 851006250000 |