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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 9 |
| 7 | 21 |
| 8 | 56 |
| 9 | 148 |
| 10 | 428 |
| 11 | 1305 |
| 12 | 4191 |
| 13 | 14140 |
| 14 | 50159 |
| 15 | 185987 |
| 16 | 720298 |
| 17 | 2905512 |
| 18 | 12180208 |
| 19 | 52951701 |
| 20 | 238253067 |
| 21 | 1107432714 |
| 22 | 5308573473 |
| 23 | 26202267612 |
| 24 | 132977762151 |
| 25 | 692996060768 |