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 | -1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 3 |
| 6 | -34 |
| 7 | -59 |
| 8 | -9 |
| 9 | 176 |
| 10 | 1749 |
| 11 | 490 |
| 12 | -842 |
| 13 | 4297 |
| 14 | 13427 |
| 15 | -92418 |
| 16 | -253834 |
| 17 | 925307 |
| 18 | 2903111 |
| 19 | -27385699 |
| 20 | 28776158 |
| 21 | 81540379 |
| 22 | 40700461 |
| 23 | -1160432518 |
| 24 | 2692289572 |
| 25 | 175794995 |