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 | 9 |
| 2 | 135 |
| 3 | 25515 |
| 4 | 45927 |
| 5 | 12629925 |
| 6 | 4433103675 |
| 7 | 1396427657625 |
| 8 | 23739270179625 |
| 9 | 21920842083865725 |
| 10 | 34525326282088516875 |
| 11 | 8734907549368394769375 |
| 12 | 17688187787470999407984375 |
| 13 | 413903594226821386146834375 |