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 | 1 |
| 2 | -4 |
| 3 | 1 |
| 4 | 46 |
| 5 | -129 |
| 6 | -405 |
| 7 | 3319 |
| 8 | -1617 |
| 9 | -59258 |
| 10 | 199541 |
| 11 | 642170 |
| 12 | -6038395 |
| 13 | 3886091 |
| 14 | 119884973 |
| 15 | -440626784 |
| 16 | -1367688245 |
| 17 | 14055527190 |
| 18 | -11043763380 |
| 19 | -290488387366 |
| 20 | 1137260033731 |
| 21 | 3336325340735 |
| 22 | -36966844508130 |
| 23 | 34098313310315 |
| 24 | 776097820004580 |