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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 15 |
| 5 | 156 |
| 6 | 4665 |
| 7 | 269618 |
| 8 | 31573327 |
| 9 | 7375159140 |
| 10 | 3450904512841 |
| 11 | 3240500443884718 |
| 12 | 6113078165054644451 |
| 13 | 23175001880311842459108 |
| 14 | 176546824267008236554238517 |
| 15 | 2701847513793569606737940203894 |
| 16 | 83036203475880811677609125194805687 |