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 | 4 |
| 4 | 12 |
| 5 | 32 |
| 6 | 112 |
| 7 | 352 |
| 8 | 1296 |
| 9 | 4448 |
| 10 | 16640 |
| 11 | 59968 |
| 12 | 231168 |
| 13 | 856960 |
| 14 | 3334400 |
| 15 | 12679424 |
| 16 | 49991424 |
| 17 | 192890880 |
| 18 | 767229952 |
| 19 | 2998427648 |
| 20 | 12015527936 |
| 21 | 47438950400 |
| 22 | 191117033472 |
| 23 | 760625733632 |
| 24 | 3082675150848 |
| 25 | 12346305839104 |
| 26 | 50223511928832 |
| 27 | 202359539335168 |