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 | 0 |
| 2 | 0 |
| 3 | -2 |
| 4 | 0 |
| 5 | -12 |
| 6 | 2 |
| 7 | -78 |
| 8 | 24 |
| 9 | -548 |
| 10 | 228 |
| 11 | -4050 |
| 12 | 2030 |
| 13 | -30960 |
| 14 | 17670 |
| 15 | -242402 |
| 16 | 152520 |
| 17 | -1932000 |
| 18 | 1312844 |
| 19 | -15612150 |
| 20 | 11297052 |
| 21 | -127551884 |
| 22 | 97291026 |
| 23 | -1051478274 |
| 24 | 838994486 |
| 25 | -8732657724 |
| 26 | 7246304736 |
| 27 | -72983051674 |
| 28 | 62686156026 |
| 29 | -613243234224 |
| 30 | 543146222970 |