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 | 0 |
| 3 | 0 |
| 4 | -7 |
| 5 | -3 |
| 6 | -17 |
| 7 | 52 |
| 8 | 51 |
| 9 | 384 |
| 10 | -227 |
| 11 | -52 |
| 12 | -6311 |
| 13 | -2722 |
| 14 | -18733 |
| 15 | 79229 |
| 16 | 67453 |
| 17 | 620385 |
| 18 | -619315 |
| 19 | 85796 |
| 20 | -13137380 |
| 21 | -595833 |
| 22 | -43282243 |
| 23 | 205480697 |
| 24 | 66895157 |
| 25 | 1551910768 |
| 26 | -2300631561 |
| 27 | 1546386060 |
| 28 | -36481481081 |
| 29 | 15982958026 |
| 30 | -135266506195 |
| 31 | 652843485153 |