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 | 3 |
| 3 | 13 |
| 4 | 61 |
| 5 | 61 |
| 6 | 421 |
| 7 | 2521 |
| 8 | 2521 |
| 9 | 2521 |
| 10 | 55441 |
| 11 | 55441 |
| 12 | 4324321 |
| 13 | 4324321 |
| 14 | 4324321 |
| 15 | 4324321 |
| 16 | 85765681 |
| 17 | 85765681 |
| 18 | 232792561 |
| 19 | 232792561 |
| 20 | 232792561 |
| 21 | 232792561 |