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 | 0 |
| 2 | -2 |
| 3 | 38 |
| 4 | -466 |
| 5 | 5070 |
| 6 | -51230 |
| 7 | 495394 |
| 8 | -4647646 |
| 9 | 42658722 |
| 10 | -385096770 |
| 11 | 3431429230 |
| 12 | -30256897090 |
| 13 | 264500216510 |
| 14 | -2295570216930 |
| 15 | 19801160761630 |
| 16 | -169902404575970 |
| 17 | 1451166299240222 |
| 18 | -12344920792691958 |
| 19 | 104644181977065306 |
| 20 | -884232602452034390 |
| 21 | 7450498211688604010 |
| 22 | -62617113713498946622 |
| 23 | 525042133132770041538 |