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 | 70 |
| 2 | 1540 |
| 3 | 18480 |
| 4 | 150150 |
| 5 | 924924 |
| 6 | 4624620 |
| 7 | 19631040 |
| 8 | 73002930 |
| 9 | 243343100 |
| 10 | 739763024 |
| 11 | 2078672960 |
| 12 | 5456516520 |
| 13 | 13495999440 |
| 14 | 31674284400 |
| 15 | 70950397056 |
| 16 | 152432493675 |
| 17 | 315413948850 |
| 18 | 630827897700 |
| 19 | 1223211990000 |
| 20 | 2305754601150 |
| 21 | 4235059471500 |
| 22 | 7595106655500 |