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 | 3 |
| 3 | 9 |
| 4 | 11 |
| 5 | 33 |
| 6 | 73 |
| 7 | 99 |
| 8 | 101 |
| 9 | 137 |
| 10 | 219 |
| 11 | 303 |
| 12 | 411 |
| 13 | 657 |
| 14 | 803 |
| 15 | 909 |
| 16 | 1111 |
| 17 | 1233 |
| 18 | 1507 |
| 19 | 2409 |
| 20 | 3333 |
| 21 | 4521 |
| 22 | 7227 |
| 23 | 7373 |
| 24 | 9999 |
| 25 | 10001 |
| 26 | 13563 |
| 27 | 13837 |
| 28 | 22119 |
| 29 | 30003 |
| 30 | 41511 |
| 31 | 66357 |
| 32 | 81103 |
| 33 | 90009 |
| 34 | 110011 |
| 35 | 124533 |
| 36 | 152207 |
| 37 | 243309 |
| 38 | 330033 |
| 39 | 456621 |
| 40 | 729927 |
| 41 | 990099 |
| 42 | 1010101 |