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 | 144 |
| 3 | 780 |
| 4 | 51205 |
| 5 | 380160 |
| 6 | 21001799 |
| 7 | 170537640 |
| 8 | 8940739824 |
| 9 | 74795194705 |
| 10 | 3852472573499 |
| 11 | 32565539635200 |
| 12 | 1666961188795475 |
| 13 | 14143261515284447 |
| 14 | 722364079570222320 |
| 15 | 6136973985625588560 |
| 16 | 313196612952258199679 |
| 17 | 2662079368040434932480 |
| 18 | 135818983640055277506397 |