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 | 3 |
| 1 | 4 |
| 2 | 12 |
| 3 | 28 |
| 4 | 72 |
| 5 | 184 |
| 6 | 480 |
| 7 | 1264 |
| 8 | 3360 |
| 9 | 8992 |
| 10 | 24192 |
| 11 | 65344 |
| 12 | 177024 |
| 13 | 480640 |
| 14 | 1307136 |
| 15 | 3559168 |
| 16 | 9699840 |
| 17 | 26452480 |
| 18 | 72173568 |
| 19 | 196989952 |
| 20 | 537802752 |
| 21 | 1468536832 |
| 22 | 4010582016 |
| 23 | 10954043392 |
| 24 | 29920862208 |
| 25 | 81733033984 |
| 26 | 223274237952 |
| 27 | 609947435008 |
| 28 | 1666309128192 |