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 | 1 |
| 2 | 5 |
| 3 | 32 |
| 4 | 292 |
| 5 | 3174 |
| 6 | 42758 |
| 7 | 659028 |
| 8 | 11725656 |
| 9 | 233646240 |
| 10 | 5183599152 |
| 11 | 126353158656 |
| 12 | 3362529785712 |
| 13 | 96896454983184 |
| 14 | 3007687250735568 |
| 15 | 100017757744279584 |
| 16 | 3547903924884082176 |
| 17 | 133715849506895518848 |
| 18 | 5336112511923188151168 |
| 19 | 224772952826373341478912 |
| 20 | 9966476790792153522756864 |