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 | 1 |
| 2 | 12 |
| 3 | 123 |
| 4 | 1235 |
| 5 | 12356 |
| 6 | 123567 |
| 7 | 1235678 |
| 8 | 12356789 |
| 9 | 1235678910 |
| 10 | 123567891011 |
| 11 | 12356789101112 |
| 12 | 1235678910111213 |
| 13 | 123567891011121314 |
| 14 | 12356789101112131415 |
| 15 | 1235678910111213141516 |
| 16 | 123567891011121314151617 |
| 17 | 12356789101112131415161718 |
| 18 | 1235678910111213141516171819 |
| 19 | 123567891011121314151617181920 |