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 | 3 |
| 3 | 7 |
| 4 | 111 |
| 5 | 343 |
| 6 | 757 |
| 7 | 10101 |
| 8 | 15751 |
| 9 | 30103 |
| 10 | 1001001 |
| 11 | 1255521 |
| 12 | 1403041 |
| 13 | 1837381 |
| 14 | 3372733 |
| 15 | 3521253 |
| 16 | 3847483 |
| 17 | 100010001 |
| 18 | 141979141 |
| 19 | 10000100001 |
| 20 | 14181118141 |
| 21 | 16112621161 |
| 22 | 35297579253 |
| 23 | 35475157453 |
| 24 | 37011411073 |
| 25 | 38735553783 |
| 26 | 1000001000001 |
| 27 | 1020505050201 |