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 | 2 |
| 4 | 4 |
| 5 | 8 |
| 6 | 14 |
| 7 | 15 |
| 8 | -31 |
| 9 | -308 |
| 10 | -1520 |
| 11 | -6138 |
| 12 | -22260 |
| 13 | -74745 |
| 14 | -234503 |
| 15 | -684931 |
| 16 | -1828743 |
| 17 | -4249668 |
| 18 | -7308296 |
| 19 | -592722 |
| 20 | 75389838 |
| 21 | 487028178 |
| 22 | 2286167634 |
| 23 | 9278268220 |
| 24 | 34247910114 |
| 25 | 117081254935 |
| 26 | 371845391419 |
| 27 | 1086709633580 |
| 28 | 2836930639816 |
| 29 | 6075557104011 |