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 | 6 |
| 2 | 28 |
| 3 | 112 |
| 4 | 456 |
| 5 | 1816 |
| 6 | 7288 |
| 7 | 29112 |
| 8 | 116536 |
| 9 | 465976 |
| 10 | 1864248 |
| 11 | 7456312 |
| 12 | 29826616 |
| 13 | 119303736 |
| 14 | 477220408 |
| 15 | 1908870712 |
| 16 | 7635504696 |
| 17 | 30541975096 |
| 18 | 122167987768 |
| 19 | 488671776312 |
| 20 | 1954687454776 |
| 21 | 7818749120056 |
| 22 | 31274997878328 |
| 23 | 125099988717112 |
| 24 | 500399960460856 |
| 25 | 2001599830658616 |
| 26 | 8006399345004088 |
| 27 | 32025597335277112 |
| 28 | 128102389430586936 |