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 | 126 |
| 1 | 210 |
| 2 | 450 |
| 3 | 1200 |
| 4 | 3750 |
| 5 | 13080 |
| 6 | 49350 |
| 7 | 197400 |
| 8 | 825750 |
| 9 | 3577080 |
| 10 | 15930150 |
| 11 | 72528600 |
| 12 | 336141750 |
| 13 | 1580449080 |
| 14 | 7518010950 |
| 15 | 36102667800 |
| 16 | 174710721750 |
| 17 | 850780489080 |
| 18 | 4164115131750 |
| 19 | 20465328135000 |
| 20 | 100917328245750 |
| 21 | 498984369457080 |
| 22 | 2472617583932550 |