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) |
|---|---|
| 2 | 1 |
| 3 | 7 |
| 4 | 36 |
| 5 | 165 |
| 6 | 715 |
| 7 | 3003 |
| 8 | 12376 |
| 9 | 50388 |
| 10 | 203490 |
| 11 | 817190 |
| 12 | 3268760 |
| 13 | 13037895 |
| 14 | 51895935 |
| 15 | 206253075 |
| 16 | 818809200 |
| 17 | 3247943160 |
| 18 | 12875774670 |
| 19 | 51021117810 |
| 20 | 202112640600 |
| 21 | 800472431850 |
| 22 | 3169870830126 |
| 23 | 12551759587422 |