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 | 0 |
| 4 | 0 |
| 5 | 4 |
| 6 | 54 |
| 7 | 1052 |
| 8 | 14611 |
| 9 | 181948 |
| 10 | 2096211 |
| 11 | 22788376 |
| 12 | 238482555 |
| 13 | 2433024862 |
| 14 | 24386079471 |
| 15 | 241344901528 |
| 16 | 2366884988610 |
| 17 | 23059199264485 |
| 18 | 223571124198381 |