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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 6 |
| 5 | 35 |
| 6 | 143 |
| 7 | 631 |
| 8 | 2747 |
| 9 | 12027 |
| 10 | 52470 |
| 11 | 227993 |
| 12 | 985522 |
| 13 | 4235295 |
| 14 | 18114067 |
| 15 | 77112058 |
| 16 | 327000797 |
| 17 | 1381807943 |
| 18 | 5821692946 |