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 | 2 |
| 1 | 1 |
| 2 | 1 |
| 3 | -3 |
| 4 | -1 |
| 5 | -29 |
| 6 | 33 |
| 7 | -315 |
| 8 | 1251 |
| 9 | -7905 |
| 10 | 48667 |
| 11 | -344723 |
| 12 | 2623549 |
| 13 | -21739937 |
| 14 | 193680399 |
| 15 | -1849767375 |
| 16 | 18840708855 |
| 17 | -203907377005 |
| 18 | 2336594492591 |
| 19 | -28262970918841 |
| 20 | 359855118160333 |
| 21 | -4810909461068941 |
| 22 | 67379837645787507 |
| 23 | -986592769520379701 |