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 | 2 |
| 1 | 6 |
| 2 | 18 |
| 3 | 52 |
| 4 | 166 |
| 5 | 524 |
| 6 | 1722 |
| 7 | 5664 |
| 8 | 19072 |
| 9 | 64408 |
| 10 | 220676 |
| 11 | 758864 |
| 12 | 2634734 |
| 13 | 9180872 |
| 14 | 32208376 |
| 15 | 113371636 |
| 16 | 401067522 |
| 17 | 1423073892 |
| 18 | 5068961452 |
| 19 | 18103192360 |
| 20 | 64853607912 |
| 21 | 232872927444 |
| 22 | 838311889890 |
| 23 | 3023961593292 |
| 24 | 10931277735230 |
| 25 | 39586258360246 |
| 26 | 143617299291242 |