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) |
|---|---|
| 3 | 0 |
| 4 | -1 |
| 5 | 210 |
| 6 | 638 |
| 7 | 1348 |
| 8 | -1 |
| 9 | 5282 |
| 10 | 7687 |
| 11 | 12453 |
| 12 | -1 |
| 13 | 24813 |
| 14 | -1 |
| 15 | 45338 |
| 16 | -1 |
| 17 | 63702 |
| 18 | 84764 |
| 19 | 109613 |
| 20 | -1 |
| 21 | 162687 |
| 22 | 155879 |
| 23 | 224244 |
| 24 | -1 |
| 25 | 303049 |
| 26 | -1 |
| 27 | 353690 |
| 28 | -1 |
| 29 | 522262 |
| 30 | 541796 |
| 31 | 651844 |
| 32 | -1 |
| 33 | 817053 |