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 | 3 |
| 2 | 13 |
| 3 | 55 |
| 4 | 240 |
| 5 | 1057 |
| 6 | 4688 |
| 7 | 20879 |
| 8 | 93250 |
| 9 | 417272 |
| 10 | 1869725 |
| 11 | 8386137 |
| 12 | 37640961 |
| 13 | 169042436 |
| 14 | 759470361 |
| 15 | 3413223919 |
| 16 | 15343588991 |
| 17 | 68988110756 |
| 18 | 310233741889 |
| 19 | 1395268187372 |
| 20 | 6275807975664 |
| 21 | 28230370862051 |
| 22 | 126996552221811 |