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 | 1 |
| 2 | 11 |
| 3 | 91 |
| 4 | 821 |
| 5 | 7381 |
| 6 | 66431 |
| 7 | 597871 |
| 8 | 5380841 |
| 9 | 48427561 |
| 10 | 435848051 |
| 11 | 3922632451 |
| 12 | 35303692061 |
| 13 | 317733228541 |
| 14 | 2859599056871 |
| 15 | 25736391511831 |
| 16 | 231627523606481 |
| 17 | 2084647712458321 |
| 18 | 18761829412124891 |
| 19 | 168856464709124011 |
| 20 | 1519708182382116101 |
| 21 | 13677373641439044901 |