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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 55 |
| 5 | 910 |
| 6 | 29400 |
| 7 | 2160250 |
| 8 | 348871589 |
| 9 | 124597748299 |
| 10 | 98443712937832 |
| 11 | 171962948531581497 |
| 12 | 664040284641624620852 |
| 13 | 5667787901436816984441067 |