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 | 1 |
| 2 | -1 |
| 3 | 1 |
| 4 | -2 |
| 5 | -1 |
| 6 | 1 |
| 7 | -5 |
| 8 | -5 |
| 9 | 1 |
| 10 | 1 |
| 11 | -12 |
| 12 | -30 |
| 13 | 12 |
| 14 | 1 |
| 15 | 1 |
| 16 | -29 |
| 17 | -174 |
| 18 | 174 |
| 19 | 29 |
| 20 | -1 |
| 21 | 1 |
| 22 | -70 |
| 23 | -1015 |
| 24 | 2436 |
| 25 | 1015 |
| 26 | -70 |
| 27 | -1 |
| 28 | 1 |
| 29 | -169 |
| 30 | -5915 |
| 31 | 34307 |
| 32 | 34307 |
| 33 | -5915 |
| 34 | -169 |
| 35 | 1 |
| 36 | 1 |
| 37 | -408 |
| 38 | -34476 |
| 39 | 482664 |
| 40 | 1166438 |
| 41 | -482664 |
| 42 | -34476 |
| 43 | 408 |
| 44 | 1 |
| 45 | 1 |
| 46 | -985 |
| 47 | -200940 |
| 48 | 6791772 |
| 49 | 39618670 |
| 50 | -39618670 |
| 51 | -6791772 |
| 52 | 200940 |
| 53 | 985 |
| 54 | -1 |