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 | 5 |
| 2 | 45 |
| 3 | 455 |
| 4 | 4845 |
| 5 | 53130 |
| 6 | 593775 |
| 7 | 6724520 |
| 8 | 76904685 |
| 9 | 886163135 |
| 10 | 10272278170 |
| 11 | 119653565850 |
| 12 | 1399358844975 |
| 13 | 16421073515280 |
| 14 | 193253756909160 |
| 15 | 2280012686716080 |
| 16 | 26958221130508525 |