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 | 6 |
| 3 | 66 |
| 4 | 426 |
| 5 | 2706 |
| 6 | 16386 |
| 7 | 99186 |
| 8 | 595986 |
| 9 | 3580986 |
| 10 | 21490986 |
| 11 | 128976186 |
| 12 | 773887386 |
| 13 | 4643505066 |
| 14 | 27861211146 |
| 15 | 167168350506 |
| 16 | 1003011186666 |
| 17 | 6018073616706 |
| 18 | 36108448196946 |
| 19 | 216650728156866 |
| 20 | 1299904407916386 |
| 21 | 7799426681319186 |
| 22 | 46796560321735986 |