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 | 1 |
| 2 | 1 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | -1 |
| 7 | -1 |
| 8 | 5 |
| 9 | -5 |
| 10 | -9 |
| 11 | 34 |
| 12 | -26 |
| 13 | -85 |
| 14 | 255 |
| 15 | -120 |
| 16 | -820 |
| 17 | 1995 |
| 18 | -245 |
| 19 | -7960 |
| 20 | 15800 |
| 21 | 4755 |
| 22 | -77175 |
| 23 | 123815 |
| 24 | 105445 |
| 25 | -743699 |
| 26 | 936529 |
| 27 | 1536534 |
| 28 | -7094790 |
| 29 | 6576505 |
| 30 | 19436599 |
| 31 | -66736489 |
| 32 | 39201501 |
| 33 | 228580275 |
| 34 | -616062205 |
| 35 | 134736984 |
| 36 | 2566177896 |
| 37 | -5546263549 |
| 38 | -1161261075 |