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) |
|---|---|
| 5 | 2 |
| 6 | 9 |
| 7 | 40 |
| 8 | 137 |
| 9 | 448 |
| 10 | 1336 |
| 11 | 3840 |
| 12 | 10540 |
| 13 | 28160 |
| 14 | 73168 |
| 15 | 186368 |
| 16 | 465808 |
| 17 | 1146880 |
| 18 | 2785024 |
| 19 | 6684672 |
| 20 | 15875520 |
| 21 | 37355520 |
| 22 | 87161600 |
| 23 | 201850880 |
| 24 | 464254208 |
| 25 | 1061158912 |
| 26 | 2411718656 |
| 27 | 5452595200 |
| 28 | 12268325888 |
| 29 | 27481079808 |
| 30 | 61303918592 |