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) |
|---|---|
| 0 | 1 |
| 1 | -18 |
| 2 | 135 |
| 3 | -504 |
| 4 | 657 |
| 5 | 2052 |
| 6 | -10071 |
| 7 | 12384 |
| 8 | 20277 |
| 9 | -83610 |
| 10 | 72090 |
| 11 | 122040 |
| 12 | -355581 |
| 13 | 245124 |
| 14 | 379512 |
| 15 | -1050624 |
| 16 | 770589 |
| 17 | 966492 |
| 18 | -2700081 |
| 19 | 1724616 |
| 20 | 2287062 |
| 21 | -5636880 |
| 22 | 3616164 |
| 23 | 4471632 |
| 24 | -11385657 |
| 25 | 6820722 |
| 26 | 8554194 |
| 27 | -19963440 |
| 28 | 12302568 |
| 29 | 14113332 |
| 30 | -34631226 |
| 31 | 19737936 |