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 | 4 |
| 2 | 14 |
| 3 | 64 |
| 4 | 352 |
| 5 | 2192 |
| 6 | 14624 |
| 7 | 99880 |
| 8 | 699252 |
| 9 | 4971184 |
| 10 | 35792568 |
| 11 | 260301176 |
| 12 | 1908882592 |
| 13 | 14096303344 |
| 14 | 104715443852 |
| 15 | 781874941184 |
| 16 | 5864062367252 |
| 17 | 44152937528384 |
| 18 | 333599974922264 |
| 19 | 2528336632928152 |
| 20 | 19215358428046176 |
| 21 | 146402730743992960 |
| 22 | 1117984489446008100 |