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) |
|---|---|
| 3 | 1 |
| 4 | 3 |
| 5 | 9 |
| 6 | 25 |
| 7 | 69 |
| 8 | 186 |
| 9 | 503 |
| 10 | 1353 |
| 11 | 3651 |
| 12 | 9865 |
| 13 | 26748 |
| 14 | 72729 |
| 15 | 198447 |
| 16 | 543159 |
| 17 | 1491402 |
| 18 | 4107152 |
| 19 | 11342826 |
| 20 | 31408719 |
| 21 | 87189987 |
| 22 | 242603970 |
| 23 | 676524372 |
| 24 | 1890436117 |
| 25 | 5292722721 |
| 26 | 14845095153 |
| 27 | 41708679697 |
| 28 | 117372283086 |
| 29 | 330795842217 |