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 | 2835 |
| 4 | 70875 |
| 5 | 1913625 |
| 6 | 63149625 |
| 7 | 2210236875 |
| 8 | 86199238125 |
| 9 | 3878965715625 |
| 10 | 190069320065625 |
| 11 | 9693535323346875 |
| 12 | 533144442784078125 |
| 13 | 30389233238692453125 |
| 14 | 1914521694037624546875 |
| 15 | 124443910112445595546875 |
| 16 | 8586629797758746092734375 |