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 | 225 |
| 2 | 5625 |
| 3 | 22500 |
| 4 | 562500 |
| 5 | 2250000 |
| 6 | 5405625 |
| 7 | 23765625 |
| 8 | 56250000 |
| 9 | 225000000 |
| 10 | 540562500 |
| 11 | 2127515625 |
| 12 | 2376562500 |
| 13 | 5625000000 |
| 14 | 22500000000 |
| 15 | 54056250000 |
| 16 | 58503515625 |
| 17 | 212751562500 |
| 18 | 237656250000 |
| 19 | 562500000000 |
| 20 | 2250000000000 |
| 21 | 5405625000000 |
| 22 | 5850351562500 |