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 | 25 |
| 2 | 2500 |
| 3 | 7225 |
| 4 | 75625 |
| 5 | 250000 |
| 6 | 722500 |
| 7 | 2325625 |
| 8 | 7562500 |
| 9 | 25000000 |
| 10 | 72250000 |
| 11 | 232562500 |
| 12 | 268140625 |
| 13 | 756250000 |
| 14 | 2500000000 |
| 15 | 7225000000 |
| 16 | 23256250000 |
| 17 | 26814062500 |
| 18 | 68971890625 |
| 19 | 75625000000 |
| 20 | 250000000000 |
| 21 | 722500000000 |