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 | 2 |
| 2 | 6 |
| 3 | 16 |
| 4 | 40 |
| 5 | 92 |
| 6 | 192 |
| 7 | 352 |
| 8 | 528 |
| 9 | 512 |
| 10 | -192 |
| 11 | -2128 |
| 12 | -3840 |
| 13 | 5888 |
| 14 | 69056 |
| 15 | 299264 |
| 16 | 917760 |
| 17 | 2125184 |
| 18 | 3258368 |
| 19 | -117760 |
| 20 | -23297536 |
| 21 | -103321600 |
| 22 | -295843840 |
| 23 | -577744128 |
| 24 | -416948224 |
| 25 | 2490589184 |
| 26 | 14821469184 |
| 27 | 50063536128 |