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 | 57 |
| 4 | 736 |
| 5 | 11985 |
| 6 | 235296 |
| 7 | 5403937 |
| 8 | 142073856 |
| 9 | 4206560769 |
| 10 | 138483596800 |
| 11 | 5017244970441 |
| 12 | 198363105460224 |
| 13 | 8498001799768273 |
| 14 | 392127481640165376 |
| 15 | 19388814120804416625 |
| 16 | 1022681739669784231936 |
| 17 | 57317273018414456262273 |
| 18 | 3401527253966521309200384 |