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) |
|---|---|
| 0 | 2 |
| 1 | 5 |
| 2 | 47 |
| 3 | 449 |
| 4 | 4447 |
| 5 | 44449 |
| 6 | 444449 |
| 7 | 4444469 |
| 8 | 44444453 |
| 9 | 444444457 |
| 10 | 4444444447 |
| 11 | 44444444497 |
| 12 | 444444444461 |
| 13 | 4444444444493 |
| 14 | 44444444444459 |
| 15 | 444444444444461 |
| 16 | 4444444444444463 |
| 17 | 44444444444444461 |
| 18 | 444444444444444469 |
| 19 | 4444444444444444537 |
| 20 | 44444444444444444447 |