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 | -1 |
| 4 | 0 |
| 5 | -3 |
| 6 | 1 |
| 7 | -9 |
| 8 | 6 |
| 9 | -29 |
| 10 | 27 |
| 11 | -99 |
| 12 | 112 |
| 13 | -351 |
| 14 | 450 |
| 15 | -1275 |
| 16 | 1782 |
| 17 | -4704 |
| 18 | 6998 |
| 19 | -17531 |
| 20 | 27324 |
| 21 | -65758 |
| 22 | 106211 |
| 23 | -247669 |
| 24 | 411291 |
| 25 | -935107 |
| 26 | 1587391 |
| 27 | -3535398 |
| 28 | 6108103 |
| 29 | -13373929 |
| 30 | 23438144 |
| 31 | -50592067 |
| 32 | 89703467 |
| 33 | -191306745 |
| 34 | 342473589 |