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) |
|---|---|
| 0 | 1 |
| 1 | 11 |
| 2 | 31 |
| 3 | 89 |
| 4 | 257 |
| 5 | 745 |
| 6 | 2165 |
| 7 | 6303 |
| 8 | 18375 |
| 9 | 53625 |
| 10 | 156629 |
| 11 | 457795 |
| 12 | 1338779 |
| 13 | 3916897 |
| 14 | 11463989 |
| 15 | 33563035 |
| 16 | 98286811 |
| 17 | 287884769 |
| 18 | 843365485 |
| 19 | 2471005371 |
| 20 | 7240717539 |
| 21 | 21219286113 |
| 22 | 62189049541 |
| 23 | 182274146987 |
| 24 | 534268171099 |