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 | 13 |
| 3 | 911 |
| 4 | 5791 |
| 5 | 79111 |
| 6 | 31051 |
| 7 | 1232527 |
| 8 | 23252729 |
| 9 | 113151719 |
| 10 | 2527293133 |
| 11 | 57911131517 |
| 12 | 991011031051 |
| 13 | 6769717375777 |
| 14 | 13579111315171 |
| 15 | 135791113151719 |
| 16 | 4547495153555759 |
| 17 | 31517192123252729 |
| 18 | 719212325272931333 |
| 19 | 1131517192123252729 |
| 20 | 71921232527293133353 |