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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | -1 |
| 4 | 2 |
| 5 | -5 |
| 6 | 12 |
| 7 | -26 |
| 8 | 52 |
| 9 | -101 |
| 10 | 201 |
| 11 | -422 |
| 12 | 927 |
| 13 | -2070 |
| 14 | 4579 |
| 15 | -9894 |
| 16 | 20789 |
| 17 | -42517 |
| 18 | 84937 |
| 19 | -166570 |
| 20 | 322700 |
| 21 | -622500 |
| 22 | 1207056 |
| 23 | -2376168 |
| 24 | 4787523 |
| 25 | -9908610 |
| 26 | 21021499 |
| 27 | -45404102 |
| 28 | 98952388 |
| 29 | -215756156 |
| 30 | 467541948 |
| 31 | -1002478352 |
| 32 | 2121546013 |
| 33 | -4427208709 |
| 34 | 9110572776 |
| 35 | -18503242145 |
| 36 | 37135048484 |
| 37 | -73759839074 |