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 | 0 |
| 1 | 21 |
| 2 | 168 |
| 3 | 756 |
| 4 | 2520 |
| 5 | 6930 |
| 6 | 16632 |
| 7 | 36036 |
| 8 | 72072 |
| 9 | 135135 |
| 10 | 240240 |
| 11 | 408408 |
| 12 | 668304 |
| 13 | 1058148 |
| 14 | 1627920 |
| 15 | 2441880 |
| 16 | 3581424 |
| 17 | 5148297 |
| 18 | 7268184 |
| 19 | 10094700 |
| 20 | 13813800 |
| 21 | 18648630 |
| 22 | 24864840 |
| 23 | 32776380 |
| 24 | 42751800 |
| 25 | 55221075 |
| 26 | 70682976 |
| 27 | 89713008 |
| 28 | 112971936 |
| 29 | 141214920 |
| 30 | 175301280 |