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 | 0 |
| 1 | 4 |
| 2 | 28 |
| 3 | 124 |
| 4 | 444 |
| 5 | 1404 |
| 6 | 4092 |
| 7 | 11260 |
| 8 | 29692 |
| 9 | 75772 |
| 10 | 188412 |
| 11 | 458748 |
| 12 | 1097724 |
| 13 | 2588668 |
| 14 | 6029308 |
| 15 | 13893628 |
| 16 | 31719420 |
| 17 | 71827452 |
| 18 | 161480700 |
| 19 | 360710140 |
| 20 | 801112060 |
| 21 | 1769996284 |
| 22 | 3892314108 |
| 23 | 8522825724 |
| 24 | 18589155324 |
| 25 | 40399536124 |
| 26 | 87509958652 |