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) |
|---|---|
| 2 | 1 |
| 3 | 5 |
| 4 | 40 |
| 5 | 644 |
| 6 | 21496 |
| 7 | 1471460 |
| 8 | 204062440 |
| 9 | 56865072164 |
| 10 | 31688930152696 |
| 11 | 35223651007587140 |
| 12 | 78001790003385408040 |
| 13 | 343983307379873262633284 |
| 14 | 3020895063527811952260491896 |
| 15 | 52843677532033943174017588842020 |
| 16 | 1841795434229559227318546660111716840 |