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 | 0 |
| 2 | 2 |
| 3 | 5 |
| 4 | 23 |
| 5 | 106 |
| 6 | 537 |
| 7 | 3143 |
| 8 | 20485 |
| 9 | 143747 |
| 10 | 1078660 |
| 11 | 8680687 |
| 12 | 74914773 |
| 13 | 690204588 |
| 14 | 6749661220 |
| 15 | 69732043730 |
| 16 | 758671016406 |
| 17 | 8674112392913 |
| 18 | 104037242257509 |
| 19 | 1306629414101911 |
| 20 | 17148719951169617 |
| 21 | 234689253311285406 |
| 22 | 3342159005325362828 |
| 23 | 49430840838485256475 |