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 | 2 |
| 1 | 11 |
| 2 | 64 |
| 3 | 426 |
| 4 | 3216 |
| 5 | 27240 |
| 6 | 256320 |
| 7 | 2656080 |
| 8 | 30078720 |
| 9 | 369774720 |
| 10 | 4906137600 |
| 11 | 69894316800 |
| 12 | 1064341555200 |
| 13 | 17255074636800 |
| 14 | 296754903244800 |
| 15 | 5396772116736000 |
| 16 | 103484118786048000 |
| 17 | 2086818140639232000 |
| 18 | 44150769074700288000 |
| 19 | 977904962186600448000 |