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 | 2 |
| 2 | 4 |
| 3 | 14 |
| 4 | 140 |
| 5 | 4964 |
| 6 | 808870 |
| 7 | 726210606 |
| 8 | 4161522164020 |
| 9 | 170403742275382924 |
| 10 | 54674613696351170731038 |
| 11 | 148019646825727958873435181692 |
| 12 | 3596203368022579371689526442266893534 |