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 | -3 |
| 3 | -26 |
| 4 | 161 |
| 5 | 2876 |
| 6 | -27755 |
| 7 | -740536 |
| 8 | 9722113 |
| 9 | 343603216 |
| 10 | -5707904499 |
| 11 | -250756091552 |
| 12 | 5039646554593 |
| 13 | 264489160965056 |
| 14 | -6237995487261915 |
| 15 | -380574552503498624 |
| 16 | 10303367499652761601 |
| 17 | 716309568462681538816 |
| 18 | -21891769059478538933603 |