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 | 1 |
| 3 | 0 |
| 4 | -5 |
| 5 | -21 |
| 6 | -59 |
| 7 | -117 |
| 8 | -96 |
| 9 | 473 |
| 10 | 3065 |
| 11 | 10946 |
| 12 | 27425 |
| 13 | 39787 |
| 14 | -46771 |
| 15 | -598587 |
| 16 | -2607973 |
| 17 | -7726692 |
| 18 | -15044242 |
| 19 | -3990122 |
| 20 | 123643981 |
| 21 | 680120511 |
| 22 | 2337866969 |
| 23 | 5550672915 |
| 24 | 6054525814 |
| 25 | -23115014733 |
| 26 | -181704066985 |
| 27 | -726923651722 |
| 28 | -2017980693299 |
| 29 | -3365063873213 |