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 | -3 |
| 2 | 10 |
| 3 | -35 |
| 4 | 127 |
| 5 | -472 |
| 6 | 1787 |
| 7 | -6855 |
| 8 | 26572 |
| 9 | -103765 |
| 10 | 407695 |
| 11 | -1608378 |
| 12 | 6369117 |
| 13 | -25271183 |
| 14 | 100542930 |
| 15 | -400114103 |
| 16 | 1597052419 |
| 17 | -6359524256 |
| 18 | 25481982047 |
| 19 | -101103395443 |
| 20 | 409291679676 |
| 21 | -1592903606657 |
| 22 | 6729506287091 |
| 23 | -23748796926026 |
| 24 | 123501587468073 |
| 25 | -227183793907851 |