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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 18 |
| 4 | 144 |
| 5 | 1196 |
| 6 | 10122 |
| 7 | 92280 |
| 8 | 821038 |
| 9 | 6991890 |
| 10 | 58992846 |
| 11 | 496243152 |
| 12 | 4159529298 |
| 13 | 34612046520 |
| 14 | 286233965312 |
| 15 | 2357133355050 |
| 16 | 19343135795244 |
| 17 | 158206906810656 |
| 18 | 1289891352293998 |
| 19 | 10487551431195780 |
| 20 | 85061169561727062 |
| 21 | 688372469609962898 |
| 22 | 5559403964257012514 |