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 | 4 |
| 2 | 24 |
| 3 | 164 |
| 4 | 1208 |
| 5 | 9348 |
| 6 | 74920 |
| 7 | 616420 |
| 8 | 5176296 |
| 9 | 44182916 |
| 10 | 382205048 |
| 11 | 3343343268 |
| 12 | 29523386968 |
| 13 | 262826367748 |
| 14 | 2356256046216 |
| 15 | 21254326842596 |
| 16 | 192766180154120 |
| 17 | 1756758963727620 |
| 18 | 16079466335134168 |
| 19 | 147748236828875428 |
| 20 | 1362397741935948024 |
| 21 | 12603116216808465284 |
| 22 | 116929440001191010664 |