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 | 7 |
| 2 | 77 |
| 3 | 735 |
| 4 | 6517 |
| 5 | 55223 |
| 6 | 453789 |
| 7 | 3647119 |
| 8 | 28824005 |
| 9 | 224827239 |
| 10 | 1735205101 |
| 11 | 13276336703 |
| 12 | 100843663893 |
| 13 | 761270796055 |
| 14 | 5716451614013 |
| 15 | 42728053589487 |
| 16 | 318086621166181 |
| 17 | 2359538070441671 |
| 18 | 17447288549040525 |
| 19 | 128644674234925471 |
| 20 | 946108300385970869 |