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 | 1 |
| 1 | 3 |
| 2 | 15 |
| 3 | 98 |
| 4 | 756 |
| 5 | 6534 |
| 6 | 61347 |
| 7 | 613470 |
| 8 | 6447012 |
| 9 | 70526404 |
| 10 | 797490876 |
| 11 | 9271926888 |
| 12 | 110380082000 |
| 13 | 1341117996300 |
| 14 | 16586474042475 |
| 15 | 208360804638150 |
| 16 | 2653858669601700 |
| 17 | 34220809160653500 |
| 18 | 446174168961282300 |
| 19 | 5875592302944678600 |
| 20 | 78078028942687784400 |