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 | 3 |
| 2 | 7 |
| 3 | 31 |
| 4 | 97 |
| 5 | 313 |
| 6 | 997 |
| 7 | 3137 |
| 8 | 9973 |
| 9 | 31607 |
| 10 | 99991 |
| 11 | 316223 |
| 12 | 999983 |
| 13 | 3162277 |
| 14 | 9999991 |
| 15 | 31622743 |
| 16 | 99999989 |
| 17 | 316227731 |
| 18 | 999999937 |
| 19 | 3162277633 |
| 20 | 9999999967 |
| 21 | 31622776589 |
| 22 | 99999999977 |
| 23 | 316227766003 |
| 24 | 999999999989 |
| 25 | 3162277660153 |
| 26 | 9999999999971 |
| 27 | 31622776601657 |