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) |
|---|---|
| 2 | 1 |
| 3 | 4 |
| 4 | 16 |
| 5 | 85 |
| 6 | 646 |
| 7 | 6664 |
| 8 | 86731 |
| 9 | 1354630 |
| 10 | 24607816 |
| 11 | 509000899 |
| 12 | 11802833296 |
| 13 | 303129872500 |
| 14 | 8539567141561 |
| 15 | 261785254856584 |
| 16 | 8674697402099836 |
| 17 | 308953306192527445 |
| 18 | 11768768651529113506 |
| 19 | 477433786852228938844 |