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 | 3 |
| 2 | 3003 |
| 3 | 33153 |
| 4 | 3303735 |
| 5 | 333336 |
| 6 | 333039336 |
| 7 | 13333363350 |
| 8 | 330335331336 |
| 9 | 3033333513330 |
| 10 | 303313733373336 |
| 11 | 30333330330333465 |
| 12 | 313631353332333336 |
| 13 | 330332337333331336 |
| 14 | 3333043333303433331 |
| 15 | 3333333330453337336653 |
| 16 | 30733333373333335323321 |
| 17 | 330332334339335333331336 |
| 18 | 33033333933433336339893330 |