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 | 1 |
| 2 | 0 |
| 3 | 2 |
| 4 | 6 |
| 5 | 6 |
| 6 | 14 |
| 7 | 60 |
| 8 | 120 |
| 9 | 216 |
| 10 | 732 |
| 11 | 2028 |
| 12 | 4240 |
| 13 | 11280 |
| 14 | 33696 |
| 15 | 83328 |
| 16 | 207072 |
| 17 | 591360 |
| 18 | 1606752 |
| 19 | 4102656 |
| 20 | 11172528 |
| 21 | 31167280 |
| 22 | 83112000 |
| 23 | 223249824 |
| 24 | 619860960 |
| 25 | 1699634784 |
| 26 | 4603619616 |
| 27 | 12689107200 |
| 28 | 35170240512 |
| 29 | 96523315200 |
| 30 | 265883115264 |
| 31 | 738668408064 |