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 | 7 |
| 2 | 47 |
| 3 | 67 |
| 4 | 467 |
| 5 | 647 |
| 6 | 677 |
| 7 | 4447 |
| 8 | 7477 |
| 9 | 44647 |
| 10 | 44777 |
| 11 | 46447 |
| 12 | 46477 |
| 13 | 46747 |
| 14 | 47777 |
| 15 | 64667 |
| 16 | 64747 |
| 17 | 66467 |
| 18 | 67447 |
| 19 | 67477 |
| 20 | 67777 |
| 21 | 74747 |
| 22 | 76667 |
| 23 | 76777 |
| 24 | 77447 |
| 25 | 77477 |
| 26 | 77647 |
| 27 | 77747 |
| 28 | 444677 |
| 29 | 444767 |
| 30 | 446447 |
| 31 | 446477 |
| 32 | 446647 |
| 33 | 446767 |
| 34 | 447467 |
| 35 | 447677 |
| 36 | 464447 |
| 37 | 464467 |
| 38 | 464647 |
| 39 | 464747 |