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 | 6 |
| 2 | 30 |
| 3 | 144 |
| 4 | 666 |
| 5 | 3024 |
| 6 | 13476 |
| 7 | 59328 |
| 8 | 258354 |
| 9 | 1115856 |
| 10 | 4784508 |
| 11 | 20393856 |
| 12 | 86473548 |
| 13 | 365034816 |
| 14 | 1534827960 |
| 15 | 6431000832 |
| 16 | 26862228450 |