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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | -2 |
| 4 | -16 |
| 5 | -20 |
| 6 | 56 |
| 7 | 232 |
| 8 | 128 |
| 9 | -1136 |
| 10 | -3040 |
| 11 | 736 |
| 12 | 19712 |
| 13 | 35008 |
| 14 | -48256 |
| 15 | -306560 |
| 16 | -323584 |
| 17 | 1192192 |
| 18 | 4325888 |
| 19 | 1498624 |
| 20 | -22958080 |
| 21 | -54907904 |
| 22 | 27932672 |
| 23 | 385312768 |
| 24 | 603029504 |
| 25 | -1105817600 |
| 26 | -5829812224 |
| 27 | -5024718848 |
| 28 | 24929435648 |
| 29 | 80007184384 |