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 | 0 |
| 3 | -1 |
| 4 | -1 |
| 5 | -3 |
| 6 | -1 |
| 7 | -6 |
| 8 | -8 |
| 9 | -10 |
| 10 | -7 |
| 11 | -4 |
| 12 | 2 |
| 13 | 2 |
| 14 | -14 |
| 15 | -90 |
| 16 | -318 |
| 17 | -896 |
| 18 | -2166 |
| 19 | -4691 |
| 20 | -9298 |
| 21 | -17175 |
| 22 | -30007 |
| 23 | -50261 |
| 24 | -81664 |
| 25 | -129637 |
| 26 | -200973 |
| 27 | -301205 |
| 28 | -426500 |
| 29 | -545183 |
| 30 | -561511 |
| 31 | -252122 |
| 32 | 836543 |
| 33 | 3542930 |
| 34 | 9312475 |
| 35 | 20508985 |
| 36 | 40858087 |
| 37 | 76119037 |
| 38 | 135203839 |
| 39 | 232236417 |
| 40 | 390709345 |
| 41 | 652711050 |
| 42 | 1101492173 |
| 43 | 1921013671 |
| 44 | 3558812217 |
| 45 | 7170401227 |
| 46 | 15800043812 |
| 47 | 37400877416 |