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 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 12 |
| 5 | 32 |
| 6 | 89 |
| 7 | 246 |
| 8 | 685 |
| 9 | 1912 |
| 10 | 5355 |
| 11 | 15038 |
| 12 | 42339 |
| 13 | 119484 |
| 14 | 337935 |
| 15 | 957738 |
| 16 | 2719539 |
| 17 | 7736208 |
| 18 | 22044444 |
| 19 | 62916696 |
| 20 | 179841270 |
| 21 | 514793944 |
| 22 | 1475586687 |
| 23 | 4234989242 |
| 24 | 12169352003 |
| 25 | 35009302296 |
| 26 | 100826681530 |
| 27 | 290683486132 |
| 28 | 838873595124 |