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 | -6 |
| 4 | -26 |
| 5 | -134 |
| 6 | -778 |
| 7 | -4950 |
| 8 | -33946 |
| 9 | -248230 |
| 10 | -1921130 |
| 11 | -15650358 |
| 12 | -133644026 |
| 13 | -1192354310 |
| 14 | -11084816458 |
| 15 | -107138260758 |
| 16 | -1074526263898 |
| 17 | -11163814083430 |
| 18 | -119971275641642 |
| 19 | -1331739929195766 |
| 20 | -15250978417105082 |
| 21 | -179975143242023366 |