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 | 0 |
| 3 | 1 |
| 4 | 4 |
| 5 | 14 |
| 6 | 48 |
| 7 | 165 |
| 8 | 568 |
| 9 | 1954 |
| 10 | 6717 |
| 11 | 23082 |
| 12 | 79307 |
| 13 | 272470 |
| 14 | 936065 |
| 15 | 3215741 |
| 16 | 11047122 |
| 17 | 37950140 |
| 18 | 130369334 |
| 19 | 447853808 |
| 20 | 1538496047 |
| 21 | 5285135093 |
| 22 | 18155807539 |
| 23 | 62369881206 |
| 24 | 214256590058 |
| 25 | 736026444181 |
| 26 | 2528439830821 |