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 | 0 |
| 2 | 9 |
| 3 | 25 |
| 4 | 2025 |
| 5 | 13225 |
| 6 | 1974025 |
| 7 | 4862025 |
| 8 | 6943225 |
| 9 | 60415182025 |
| 10 | 207612366025 |
| 11 | 916408817340025 |
| 12 | 9960302475729225 |
| 13 | 153668543313582025 |
| 14 | 1978088677245614025 |
| 15 | 13876266042653742025 |
| 16 | 20761288044852366025 |
| 17 | 47285734107144405625 |
| 18 | 406066810454367265225 |