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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 5 |
| 7 | 14 |
| 8 | 28 |
| 9 | 42 |
| 10 | 42 |
| 11 | 0 |
| 12 | -131 |
| 13 | -417 |
| 14 | -924 |
| 15 | -1652 |
| 16 | -2380 |
| 17 | -2380 |
| 18 | 0 |
| 19 | 7753 |
| 20 | 25213 |
| 21 | 56714 |
| 22 | 102256 |
| 23 | 147798 |
| 24 | 147798 |
| 25 | 0 |
| 26 | -479779 |
| 27 | -1557649 |
| 28 | -3499720 |
| 29 | -6305992 |
| 30 | -9112264 |
| 31 | -9112264 |
| 32 | 0 |
| 33 | 29587889 |
| 34 | 96072133 |
| 35 | 215873462 |
| 36 | 388991876 |
| 37 | 562110290 |
| 38 | 562110290 |
| 39 | 0 |