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) |
|---|---|
| 1 | 9 |
| 2 | 22 |
| 3 | 66 |
| 4 | 212 |
| 5 | 716 |
| 6 | 2447 |
| 7 | 8312 |
| 8 | 28118 |
| 9 | 95066 |
| 10 | 321480 |
| 11 | 1087248 |
| 12 | 3677451 |
| 13 | 12439185 |
| 14 | 42076051 |
| 15 | 142321098 |
| 16 | 481394558 |
| 17 | 1628298753 |
| 18 | 5507667897 |
| 19 | 18629517012 |
| 20 | 63013782841 |
| 21 | 213142264885 |
| 22 | 720947466146 |
| 23 | 2438583756862 |
| 24 | 8248438798128 |