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 | 4 |
| 2 | 9 |
| 3 | 64 |
| 4 | -1 |
| 5 | 144 |
| 6 | 625 |
| 7 | 324 |
| 8 | 2601 |
| 9 | -1 |
| 10 | 154449 |
| 11 | 260100 |
| 12 | 1681 |
| 13 | 898704 |
| 14 | 27225 |
| 15 | 114244 |
| 16 | -1 |
| 17 | 278784 |
| 18 | 223729 |
| 19 | 4410000 |
| 20 | 25281 |
| 21 | 12888100 |
| 22 | 4730625 |
| 23 | 1512900 |
| 24 | 4774225 |
| 25 | -1 |
| 26 | 8208225 |
| 27 | 6130576 |
| 28 | 1121481 |
| 29 | 12744900 |
| 30 | 34586161 |
| 31 | 2433600 |
| 32 | 45360225 |
| 33 | 9784384 |
| 34 | 1271279025 |
| 35 | 64064016 |
| 36 | -1 |
| 37 | 69956496 |