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 | 4 |
| 4 | 14 |
| 5 | 50 |
| 6 | 187 |
| 7 | 738 |
| 8 | 3084 |
| 9 | 13652 |
| 10 | 63917 |
| 11 | 315736 |
| 12 | 1641314 |
| 13 | 8956110 |
| 14 | 51175799 |
| 15 | 305527878 |
| 16 | 1901829488 |
| 17 | 12319405728 |
| 18 | 82896050937 |
| 19 | 578485474092 |
| 20 | 4180313933206 |
| 21 | 31237475311690 |
| 22 | 241063266361235 |
| 23 | 1918899090047882 |