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 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 24 |
| 6 | 60 |
| 7 | 156 |
| 8 | 410 |
| 9 | 1092 |
| 10 | 2952 |
| 11 | 8052 |
| 12 | 22140 |
| 13 | 61320 |
| 14 | 170820 |
| 15 | 478288 |
| 16 | 1345210 |
| 17 | 3798240 |
| 18 | 10761660 |
| 19 | 30585828 |
| 20 | 87169608 |
| 21 | 249055976 |
| 22 | 713205900 |
| 23 | 2046590844 |
| 24 | 5883948540 |
| 25 | 16945772184 |
| 26 | 48882035160 |
| 27 | 141214767876 |