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 | 5 |
| 2 | 45 |
| 3 | 335 |
| 4 | 2385 |
| 5 | 16775 |
| 6 | 117585 |
| 7 | 823415 |
| 8 | 5764545 |
| 9 | 40353095 |
| 10 | 282474225 |
| 11 | 1977324695 |
| 12 | 13841283105 |
| 13 | 96889002215 |
| 14 | 678223056465 |
| 15 | 4747561477175 |
| 16 | 33232930504065 |
| 17 | 232630513856135 |
| 18 | 1628413597648305 |
| 19 | 11398895184848855 |
| 20 | 79792266296563425 |
| 21 | 558545864081186855 |
| 22 | 3909821048578793745 |