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 | 0 |
| 2 | 1 |
| 3 | 8 |
| 4 | 80 |
| 5 | 1088 |
| 6 | 19232 |
| 7 | 424400 |
| 8 | 11361786 |
| 9 | 361058000 |
| 10 | 13386003873 |
| 11 | 570886397340 |
| 12 | 27681861184474 |
| 13 | 1511143062540976 |
| 14 | 92091641176725504 |
| 15 | 6219762391554815200 |
| 16 | 462595509951068027741 |
| 17 | 37676170944802047077248 |
| 18 | 3343539821715571537772071 |
| 19 | 321874499078487207168905840 |