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 | 2 |
| 2 | 6 |
| 3 | 10 |
| 4 | 54 |
| 5 | 106 |
| 6 | 346 |
| 7 | 1410 |
| 8 | 3994 |
| 9 | 12828 |
| 10 | 46242 |
| 11 | 158252 |
| 12 | 542568 |
| 13 | 1865796 |
| 14 | 6822592 |
| 15 | 25120772 |
| 16 | 88926198 |
| 17 | 327561126 |
| 18 | 1212380122 |
| 19 | 4358259840 |
| 20 | 16111686770 |
| 21 | 59936356888 |