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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 28 |
| 6 | 131 |
| 7 | 690 |
| 8 | 4033 |
| 9 | 25864 |
| 10 | 180265 |
| 11 | 1354458 |
| 12 | 10898823 |
| 13 | 93407828 |
| 14 | 848739867 |
| 15 | 8143768538 |
| 16 | 82229315137 |
| 17 | 871067808272 |
| 18 | 9654457636241 |
| 19 | 111688595475634 |
| 20 | 1345725966256071 |
| 21 | 16854833617813388 |
| 22 | 219050429104638707 |
| 23 | 2949276326665620482 |
| 24 | 41076923039499915393 |