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 | 6 |
| 4 | 29 |
| 5 | 132 |
| 6 | 590 |
| 7 | 2628 |
| 8 | 11732 |
| 9 | 52608 |
| 10 | 237129 |
| 11 | 1074510 |
| 12 | 4893801 |
| 13 | 22395420 |
| 14 | 102943815 |
| 15 | 475139070 |
| 16 | 2201301575 |
| 17 | 10234016880 |
| 18 | 47731093715 |
| 19 | 223273611810 |
| 20 | 1047265325255 |
| 21 | 4924606035900 |
| 22 | 23211459517120 |
| 23 | 109642275853176 |
| 24 | 518959629394294 |
| 25 | 2460993383491632 |
| 26 | 11691102386417575 |