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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 0 |
| 4 | 1 |
| 5 | 0 |
| 6 | 1 |
| 7 | 0 |
| 8 | 1 |
| 9 | -1 |
| 10 | 14 |
| 11 | -140 |
| 12 | 1804 |
| 13 | -27413 |
| 14 | 487469 |
| 15 | -10026347 |
| 16 | 236192434 |
| 17 | -6317862397 |
| 18 | 190439655627 |
| 19 | -6425425249652 |
| 20 | 241207241774251 |
| 21 | -10020155328258126 |
| 22 | 458387180159766539 |
| 23 | -22989944171828251745 |
| 24 | 1259023596072554784855 |
| 25 | -75008667460769643668557 |