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 | 2 |
| 3 | -5 |
| 4 | 11 |
| 5 | -24 |
| 6 | 53 |
| 7 | -117 |
| 8 | 258 |
| 9 | -569 |
| 10 | 1255 |
| 11 | -2768 |
| 12 | 6105 |
| 13 | -13465 |
| 14 | 29698 |
| 15 | -65501 |
| 16 | 144467 |
| 17 | -318632 |
| 18 | 702765 |
| 19 | -1549997 |
| 20 | 3418626 |
| 21 | -7540017 |
| 22 | 16630031 |
| 23 | -36678688 |
| 24 | 80897393 |
| 25 | -178424817 |
| 26 | 393528322 |
| 27 | -867954037 |
| 28 | 1914332891 |
| 29 | -4222194104 |
| 30 | 9312342245 |
| 31 | -20539017381 |
| 32 | 45300228866 |
| 33 | -99912799977 |