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 | 10 |
| 3 | 121 |
| 4 | 1003 |
| 5 | 10201 |
| 6 | 100013 |
| 7 | 1018081 |
| 8 | 10000043 |
| 9 | 100140049 |
| 10 | 1000000081 |
| 11 | 10000600009 |
| 12 | 100000000147 |
| 13 | 1000006000009 |
| 14 | 10000000000073 |
| 15 | 100000380000361 |
| 16 | 1000000000000003 |
| 17 | 10000001400000049 |
| 18 | 100000000000000831 |
| 19 | 1000000014000000049 |
| 20 | 10000000000000000049 |
| 21 | 100000000380000000361 |