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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 0 |
| 4 | -8 |
| 5 | 0 |
| 6 | 96 |
| 7 | 0 |
| 8 | -2176 |
| 9 | 0 |
| 10 | 79360 |
| 11 | 0 |
| 12 | -4245504 |
| 13 | 0 |
| 14 | 313155584 |
| 15 | 0 |
| 16 | -30460116992 |
| 17 | 0 |
| 18 | 3777576173568 |
| 19 | 0 |
| 20 | -581777702256640 |
| 21 | 0 |
| 22 | 108932957168730112 |
| 23 | 0 |
| 24 | -24370173276164456448 |
| 25 | 0 |
| 26 | 6419958484945407574016 |
| 27 | 0 |
| 28 | -1967044844910430876860416 |
| 29 | 0 |
| 30 | 693575525634287935244206080 |
| 31 | 0 |