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 | 0 |
| 3 | -32 |
| 4 | 211 |
| 5 | -2914 |
| 6 | 29854 |
| 7 | -341439 |
| 8 | 3742662 |
| 9 | -41692762 |
| 10 | 461591613 |
| 11 | -5122467836 |
| 12 | 56794896388 |
| 13 | -629924960005 |
| 14 | 6985721085652 |
| 15 | -77473909014348 |
| 16 | 859194263419359 |
| 17 | -9528629686028398 |
| 18 | 105674040835291026 |
| 19 | -1171943417651373875 |
| 20 | 12997050199917354250 |
| 21 | -144139501695851560726 |
| 22 | 1598531543102764228825 |
| 23 | -17727986584911448406232 |
| 24 | 196606383515036414871336 |
| 25 | -2180398207207766329269289 |