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 | 2 |
| 3 | 5 |
| 4 | 16 |
| 5 | 52 |
| 6 | 189 |
| 7 | 683 |
| 8 | 2621 |
| 9 | 10061 |
| 10 | 40031 |
| 11 | 159201 |
| 12 | 650880 |
| 13 | 2657089 |
| 14 | 11062682 |
| 15 | 46065143 |
| 16 | 194595138 |
| 17 | 822215099 |
| 18 | 3513875245 |
| 19 | 15021070567 |
| 20 | 64785349064 |
| 21 | 279575206629 |
| 22 | 1214958544538 |
| 23 | 5283266426743 |
| 24 | 23106210465665 |
| 25 | 101120747493793 |
| 26 | 444614706427665 |