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 | 0 |
| 1 | 5 |
| 2 | 26 |
| 3 | 75 |
| 4 | 1104 |
| 5 | 3505 |
| 6 | 20312 |
| 7 | 20312 |
| 8 | 4961570 |
| 9 | 28020774 |
| 10 | 229788809 |
| 11 | 512264058 |
| 12 | 2489590801 |
| 13 | 71696026806 |
| 14 | 71696026806 |
| 15 | 71696026806 |
| 16 | 19061942066578 |
| 17 | 218459525484184 |
| 18 | 451090039471391 |