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 | 15 |
| 2 | 150 |
| 3 | 1225 |
| 4 | 8820 |
| 5 | 58212 |
| 6 | 360360 |
| 7 | 2123550 |
| 8 | 12033450 |
| 9 | 66050270 |
| 10 | 353068716 |
| 11 | 1845586470 |
| 12 | 9464546000 |
| 13 | 47738754000 |
| 14 | 237329805600 |
| 15 | 1164893795820 |
| 16 | 5653161067950 |
| 17 | 27157342385250 |
| 18 | 129275302348500 |
| 19 | 610315506350550 |
| 20 | 2859764086899720 |
| 21 | 13308425945529000 |