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 | 6 |
| 3 | 38 |
| 4 | 344 |
| 5 | 3832 |
| 6 | 51408 |
| 7 | 803952 |
| 8 | 14371456 |
| 9 | 289005440 |
| 10 | 6457624832 |
| 11 | 158719896832 |
| 12 | 4255775425536 |
| 13 | 123619815742464 |
| 14 | 3867071262472192 |
| 15 | 129610289219999744 |
| 16 | 4633674344869756928 |
| 17 | 176011269522607144960 |
| 18 | 7079115958438736363520 |