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 | 0 |
| 4 | 1 |
| 5 | -2 |
| 6 | 3 |
| 7 | -3 |
| 8 | -2 |
| 9 | 24 |
| 10 | -94 |
| 11 | 280 |
| 12 | -687 |
| 13 | 1270 |
| 14 | -655 |
| 15 | -9306 |
| 16 | 65087 |
| 17 | -306724 |
| 18 | 1202250 |
| 19 | -4033365 |
| 20 | 10855578 |
| 21 | -15470865 |
| 22 | -69819687 |
| 23 | 850568716 |
| 24 | -5679272040 |
| 25 | 30749200898 |
| 26 | -144912453016 |
| 27 | 593521998765 |
| 28 | -1956641103972 |
| 29 | 3349999455415 |
| 30 | 20123433921282 |
| 31 | -295760693980981 |