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 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 28 |
| 5 | 140 |
| 6 | 841 |
| 7 | 5887 |
| 8 | 47096 |
| 9 | 423865 |
| 10 | 4238650 |
| 11 | 46625150 |
| 12 | 559501801 |
| 13 | 7273523413 |
| 14 | 101829327782 |
| 15 | 1527439916731 |
| 16 | 24439038667696 |
| 17 | 415463657350832 |
| 18 | 7478345832314977 |
| 19 | 142088570813984563 |
| 20 | 2841771416279691260 |
| 21 | 59677199741873516461 |
| 22 | 1312898394321217362142 |