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 | 3 |
| 1 | 3 |
| 2 | 4 |
| 3 | 8 |
| 4 | 31 |
| 5 | 133 |
| 6 | 832 |
| 7 | 5113 |
| 8 | 41044 |
| 9 | 388800 |
| 10 | 3958704 |
| 11 | 39916802 |
| 12 | 518682390 |
| 13 | 6302045232 |
| 14 | 90968651712 |
| 15 | 1332614649600 |
| 16 | 22844265373440 |
| 17 | 356226551466344 |
| 18 | 7504470340300800 |
| 19 | 123358411682195904 |
| 20 | 2432902126073962432 |
| 21 | 52279222588118377280 |
| 22 | 1175121515279802150144 |