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 | 17 |
| 2 | 277 |
| 3 | 37 |
| 4 | 47 |
| 5 | 577 |
| 6 | 67 |
| 7 | -1 |
| 8 | 877 |
| 9 | 97 |
| 10 | 107 |
| 11 | 11777 |
| 12 | 127 |
| 13 | 137 |
| 14 | -1 |
| 15 | 157 |
| 16 | 167 |
| 17 | 1777 |
| 18 | 1877 |
| 19 | 197 |
| 20 | 20777777 |
| 21 | -1 |
| 22 | 227 |
| 23 | 2377 |
| 24 | 2477 |
| 25 | 257 |
| 26 | 2677 |
| 27 | 277 |
| 28 | -1 |
| 29 | 29777777777777777777777777777777777777777777777777 |
| 30 | 307 |
| 31 | 317 |
| 32 | 3277777 |