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 | 111 |
| 5 | 333 |
| 6 | 1467 |
| 7 | 6813 |
| 8 | 54279 |
| 9 | 84573 |
| 10 | 252081 |
| 11 | 607947 |
| 12 | 665667 |
| 13 | 1001001 |
| 14 | 1110519 |
| 15 | 1823841 |
| 16 | 3003003 |
| 17 | 3129201 |
| 18 | 12914001 |
| 19 | 13785399 |
| 20 | 22161609 |
| 21 | 22957083 |
| 22 | 37037037 |
| 23 | 41089203 |
| 24 | 49235049 |
| 25 | 64021761 |
| 26 | 92840751 |
| 27 | 108503721 |
| 28 | 111111111 |