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 | 4 |
| 2 | 5 |
| 3 | 15 |
| 4 | -5 |
| 5 | 111 |
| 6 | -402 |
| 7 | 2172 |
| 8 | -10892 |
| 9 | 57362 |
| 10 | -305756 |
| 11 | 1656560 |
| 12 | -9083341 |
| 13 | 50328219 |
| 14 | -281324174 |
| 15 | 1584578882 |
| 16 | -8984740332 |
| 17 | 51242962422 |
| 18 | -293772467974 |
| 19 | 1691974930794 |
| 20 | -9785378133066 |
| 21 | 56805049768410 |
| 22 | -330880419984556 |
| 23 | 1933299689139664 |
| 24 | -11328101469158229 |