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 | 4 |
| 4 | -3 |
| 5 | -6 |
| 6 | 16 |
| 7 | -7 |
| 8 | -31 |
| 9 | 61 |
| 10 | -6 |
| 11 | -147 |
| 12 | 220 |
| 13 | 68 |
| 14 | -655 |
| 15 | 739 |
| 16 | 639 |
| 17 | -2772 |
| 18 | 2233 |
| 19 | 3950 |
| 20 | -11188 |
| 21 | 5521 |
| 22 | 20805 |
| 23 | -43035 |
| 24 | 6946 |
| 25 | 99929 |
| 26 | -156856 |
| 27 | -36056 |
| 28 | 449697 |
| 29 | -534441 |
| 30 | -401009 |
| 31 | 1919588 |
| 32 | -1652011 |
| 33 | -2588174 |
| 34 | 7811784 |
| 35 | -4287447 |
| 36 | -13924295 |
| 37 | 30310973 |
| 38 | -6749830 |
| 39 | -67796411 |
| 40 | 111607044 |
| 41 | 17235948 |