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 | 4 |
| 1 | -1 |
| 2 | -1 |
| 3 | -1 |
| 4 | 7 |
| 5 | -6 |
| 6 | -1 |
| 7 | -1 |
| 8 | 15 |
| 9 | -19 |
| 10 | 4 |
| 11 | -1 |
| 12 | 31 |
| 13 | -53 |
| 14 | 27 |
| 15 | -6 |
| 16 | 63 |
| 17 | -137 |
| 18 | 107 |
| 19 | -39 |
| 20 | 132 |
| 21 | -337 |
| 22 | 351 |
| 23 | -185 |
| 24 | 303 |
| 25 | -806 |
| 26 | 1039 |
| 27 | -721 |
| 28 | 791 |
| 29 | -1915 |
| 30 | 2884 |
| 31 | -2481 |
| 32 | 2303 |
| 33 | -4621 |
| 34 | 7683 |
| 35 | -7846 |
| 36 | 7087 |
| 37 | -11545 |
| 38 | 19987 |
| 39 | -23375 |
| 40 | 22020 |
| 41 | -30177 |
| 42 | 51519 |
| 43 | -66737 |
| 44 | 67415 |
| 45 | -82374 |
| 46 | 133215 |
| 47 | -184993 |
| 48 | 201567 |
| 49 | -232163 |
| 50 | 348804 |