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 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 0 |
| 6 | 3 |
| 7 | -4 |
| 8 | 5 |
| 9 | -24 |
| 10 | 19 |
| 11 | -76 |
| 12 | 133 |
| 13 | -208 |
| 14 | 627 |
| 15 | -852 |
| 16 | 2181 |
| 17 | -4232 |
| 18 | 7443 |
| 19 | -18012 |
| 20 | 30533 |
| 21 | -66880 |
| 22 | 133875 |
| 23 | -250724 |
| 24 | 547013 |
| 25 | -1020152 |
| 26 | 2108435 |
| 27 | -4245612 |
| 28 | 8217861 |
| 29 | -17089968 |
| 30 | 33202291 |
| 31 | -67158900 |
| 32 | 135095301 |
| 33 | -265925992 |
| 34 | 541112339 |
| 35 | -1069523580 |
| 36 | 2146659781 |
| 37 | -4309316128 |
| 38 | 8553624307 |