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 | 1 |
| 2 | 4 |
| 3 | 19 |
| 4 | 116 |
| 5 | 776 |
| 6 | 5620 |
| 7 | 42288 |
| 8 | 328756 |
| 9 | 2615104 |
| 10 | 21191904 |
| 11 | 174303163 |
| 12 | 1451430692 |
| 13 | 12211799224 |
| 14 | 103655949072 |
| 15 | 886568153744 |
| 16 | 7633233556276 |
| 17 | 66105170315084 |
| 18 | 575445692499952 |
| 19 | 5032380942945322 |
| 20 | 44191451788248416 |
| 21 | 389514699013012242 |
| 22 | 3444925385336301684 |