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 | 1 |
| 3 | 4 |
| 4 | 12 |
| 5 | 46 |
| 6 | 172 |
| 7 | 689 |
| 8 | 2763 |
| 9 | 11241 |
| 10 | 45706 |
| 11 | 186346 |
| 12 | 759375 |
| 13 | 3095191 |
| 14 | 12610825 |
| 15 | 51370336 |
| 16 | 209194923 |
| 17 | 851712069 |
| 18 | 3466881944 |