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 | 4 |
| 3 | 9 |
| 4 | 5 |
| 5 | 8 |
| 6 | 63 |
| 7 | 183 |
| 8 | 348 |
| 9 | 745 |
| 10 | 2061 |
| 11 | 5456 |
| 12 | 12991 |
| 13 | 30831 |
| 14 | 76660 |
| 15 | 192137 |
| 16 | 472597 |
| 17 | 1155032 |
| 18 | 2843007 |
| 19 | 7024935 |
| 20 | 17315404 |
| 21 | 42592489 |
| 22 | 104847389 |
| 23 | 258355104 |
| 24 | 636507775 |
| 25 | 1567442143 |
| 26 | 3859933668 |
| 27 | 9507231753 |
| 28 | 23417547813 |
| 29 | 57675809960 |
| 30 | 142047927231 |
| 31 | 349856144791 |