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 | 4 |
| 2 | 9 |
| 3 | 49 |
| 4 | 94 |
| 5 | 949 |
| 6 | 4449 |
| 7 | 4499 |
| 8 | 9449 |
| 9 | 44494 |
| 10 | 44949 |
| 11 | 44999 |
| 12 | 49949 |
| 13 | 94499 |
| 14 | 94994 |
| 15 | 99449 |
| 16 | 99494 |
| 17 | 99949 |
| 18 | 444494 |
| 19 | 444949 |
| 20 | 494449 |
| 21 | 494999 |
| 22 | 499949 |
| 23 | 944494 |
| 24 | 944949 |
| 25 | 944999 |
| 26 | 949999 |
| 27 | 994999 |
| 28 | 999494 |
| 29 | 4444449 |
| 30 | 4444499 |
| 31 | 4449949 |
| 32 | 4449999 |
| 33 | 4494449 |
| 34 | 4494499 |
| 35 | 4494949 |
| 36 | 4494999 |
| 37 | 4499449 |
| 38 | 4499494 |
| 39 | 4944449 |
| 40 | 4944499 |