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 | 9 |
| 5 | 22 |
| 6 | 58 |
| 7 | 164 |
| 8 | 496 |
| 9 | 1601 |
| 10 | 5502 |
| 11 | 20075 |
| 12 | 77531 |
| 13 | 315947 |
| 14 | 1354279 |
| 15 | 6087421 |
| 16 | 28611385 |
| 17 | 140239297 |
| 18 | 715116827 |
| 19 | 3785445032 |
| 20 | 20760746393 |
| 21 | 117759236340 |
| 22 | 689745339984 |
| 23 | 4165874930885 |
| 24 | 25911148634728 |
| 25 | 165775085602106 |
| 26 | 1089773992530717 |
| 27 | 7353740136527305 |