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 | 2 |
| 2 | 16 |
| 3 | 56 |
| 4 | 304 |
| 5 | 1280 |
| 6 | 6208 |
| 7 | 27776 |
| 8 | 130048 |
| 9 | 593408 |
| 10 | 2747392 |
| 11 | 12615680 |
| 12 | 58200064 |
| 13 | 267788288 |
| 14 | 1233977344 |
| 15 | 5681414144 |
| 16 | 26170556416 |
| 17 | 120518082560 |
| 18 | 555082842112 |
| 19 | 2556382674944 |
| 20 | 11773759455232 |
| 21 | 54224111009792 |
| 22 | 249733335482368 |