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 | 6125625 |
| 7 | 19580625 |
| 8 | 56250000 |
| 9 | 225000000 |
| 10 | 612562500 |
| 11 | 1958062500 |
| 12 | 2562890625 |
| 13 | 5625000000 |
| 14 | 22500000000 |
| 15 | 51472265625 |
| 16 | 61256250000 |
| 17 | 195806250000 |
| 18 | 256289062500 |
| 19 | 562500000000 |
| 20 | 2250000000000 |
| 21 | 5147226562500 |
| 22 | 6125625000000 |