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 | 2 |
| 2 | -2 |
| 3 | -4 |
| 4 | 14 |
| 5 | 24 |
| 6 | -92 |
| 7 | -176 |
| 8 | 694 |
| 9 | 1342 |
| 10 | -5480 |
| 11 | -10612 |
| 12 | 44532 |
| 13 | 86408 |
| 14 | -369328 |
| 15 | -717616 |
| 16 | 3109078 |
| 17 | 6046724 |
| 18 | -26473950 |
| 19 | -51523620 |
| 20 | 227477656 |
| 21 | 442950880 |
| 22 | -1969014572 |
| 23 | -3835720208 |
| 24 | 17147433572 |
| 25 | 33415180858 |
| 26 | -150096433272 |
| 27 | -292574352808 |
| 28 | 1319581377424 |
| 29 | 2572787175656 |
| 30 | -11644937717296 |