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 | 1 |
| 2 | 0 |
| 3 | 9 |
| 4 | 14 |
| 5 | 125 |
| 6 | 702 |
| 7 | 5047 |
| 8 | 40172 |
| 9 | 362949 |
| 10 | 3628100 |
| 11 | 39916811 |
| 12 | 478996746 |
| 13 | 6227020813 |
| 14 | 87178250922 |
| 15 | 1307674370745 |
| 16 | 20922789524192 |
| 17 | 355687428096017 |
| 18 | 6402373702119096 |
| 19 | 121645100408832019 |
| 20 | 2432902008136718030 |
| 21 | 51090942171709621965 |
| 22 | 1124000727777128678510 |