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 | -2 |
| 4 | -11 |
| 5 | -4 |
| 6 | 181 |
| 7 | 624 |
| 8 | -3863 |
| 9 | -37808 |
| 10 | 66121 |
| 11 | 2529440 |
| 12 | 4478365 |
| 13 | -197245632 |
| 14 | -1211701763 |
| 15 | 17275207936 |
| 16 | 226423491793 |
| 17 | -1517532372736 |
| 18 | -43068302925551 |
| 19 | 78275049887232 |
| 20 | 8876725117679941 |
| 21 | 24598365340871680 |
| 22 | -1997577117130009403 |
| 23 | -16151599386896207872 |
| 24 | 483811389670392875449 |