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 | 0 |
| 2 | 4 |
| 3 | 8 |
| 4 | 18 |
| 5 | 72 |
| 6 | 162 |
| 7 | 520 |
| 8 | 1514 |
| 9 | 4312 |
| 10 | 13242 |
| 11 | 39088 |
| 12 | 118586 |
| 13 | 361712 |
| 14 | 1103946 |
| 15 | 3403624 |
| 16 | 10513130 |
| 17 | 32614696 |
| 18 | 101530170 |
| 19 | 316770752 |
| 20 | 990771834 |
| 21 | 3104283168 |
| 22 | 9741133578 |
| 23 | 30606719000 |
| 24 | 96263812906 |
| 25 | 303028237848 |
| 26 | 954563802106 |
| 27 | 3008665176560 |
| 28 | 9487377712634 |
| 29 | 29928407213328 |