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 | 1 |
| 3 | 3 |
| 4 | 10 |
| 5 | 42 |
| 6 | 202 |
| 7 | 1146 |
| 8 | 7493 |
| 9 | 56996 |
| 10 | 508609 |
| 11 | 5414635 |
| 12 | 70214227 |
| 13 | 1134439731 |
| 14 | 23331152887 |
| 15 | 621768153861 |
| 16 | 21761221300058 |
| 17 | 1009759125475973 |
| 18 | 62534859409597022 |
| 19 | 5193886959561972984 |
| 20 | 580677490292990902682 |
| 21 | 87649885799470898359728 |
| 22 | 17907726747155924589913398 |