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 | 6 |
| 4 | 21 |
| 5 | 77 |
| 6 | 287 |
| 7 | 1079 |
| 8 | 4082 |
| 9 | 15522 |
| 10 | 59280 |
| 11 | 227240 |
| 12 | 873886 |
| 13 | 3370030 |
| 14 | 13027730 |
| 15 | 50469890 |
| 16 | 195892565 |
| 17 | 761615285 |
| 18 | 2965576715 |
| 19 | 11563073315 |
| 20 | 45141073925 |
| 21 | 176423482325 |
| 22 | 690215089745 |
| 23 | 2702831489825 |
| 24 | 10593202603775 |
| 25 | 41550902139551 |
| 26 | 163099562175851 |