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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 6 |
| 4 | 18 |
| 5 | 46 |
| 6 | 115 |
| 7 | 374 |
| 8 | 1204 |
| 9 | 3752 |
| 10 | 11300 |
| 11 | 34324 |
| 12 | 105124 |
| 13 | 322989 |
| 14 | 989692 |
| 15 | 3028484 |
| 16 | 9267328 |
| 17 | 28374898 |
| 18 | 86891022 |
| 19 | 266058106 |
| 20 | 814585879 |
| 21 | 2494006074 |
| 22 | 7636057864 |
| 23 | 23380074400 |
| 24 | 71584762200 |
| 25 | 219176102664 |
| 26 | 671066472872 |
| 27 | 2054652945289 |