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 | -3 |
| 5 | 3 |
| 6 | -3 |
| 7 | 5 |
| 8 | -8 |
| 9 | 5 |
| 10 | -11 |
| 11 | 36 |
| 12 | -45 |
| 13 | 41 |
| 14 | -72 |
| 15 | 142 |
| 16 | -223 |
| 17 | 311 |
| 18 | -493 |
| 19 | 851 |
| 20 | -1243 |
| 21 | 1823 |
| 22 | -3204 |
| 23 | 5336 |
| 24 | -7906 |
| 25 | 12083 |
| 26 | -20134 |
| 27 | 33133 |
| 28 | -51685 |
| 29 | 81568 |
| 30 | -133556 |
| 31 | 215363 |
| 32 | -340155 |
| 33 | 547916 |
| 34 | -895895 |
| 35 | 1442323 |
| 36 | -2300704 |
| 37 | 3718260 |
| 38 | -6056908 |
| 39 | 9787064 |
| 40 | -15755664 |
| 41 | 25541623 |