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) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 17 |
| 5 | 91 |
| 6 | 758 |
| 7 | 10094 |
| 8 | 215094 |
| 9 | 7378716 |
| 10 | 408057060 |
| 11 | 36439600740 |
| 12 | 5258207000160 |
| 13 | 1226732478115680 |
| 14 | 462844011818878560 |
| 15 | 282472779283129656000 |
| 16 | 278884771717353348456000 |
| 17 | 445462025196173918554440000 |
| 18 | 1151206495594319717393795136000 |