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) |
|---|---|
| 1 | 0 |
| 2 | 8 |
| 3 | 72 |
| 4 | 450 |
| 5 | 2420 |
| 6 | 12010 |
| 7 | 56754 |
| 8 | 259628 |
| 9 | 1160936 |
| 10 | 5105144 |
| 11 | 22166760 |
| 12 | 95301932 |
| 13 | 406510934 |
| 14 | 1722863088 |
| 15 | 7263024536 |
| 16 | 30481913682 |
| 17 | 127442700854 |
| 18 | 531088604958 |
| 19 | 2206913662766 |
| 20 | 9147940180122 |
| 21 | 37836235984334 |
| 22 | 156187232759706 |