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 | 6 |
| 5 | 18 |
| 6 | 42 |
| 7 | 111 |
| 8 | 279 |
| 9 | 752 |
| 10 | 1990 |
| 11 | 5376 |
| 12 | 14707 |
| 13 | 40465 |
| 14 | 111970 |
| 15 | 311997 |
| 16 | 873239 |
| 17 | 2455818 |
| 18 | 6933060 |
| 19 | 19640273 |
| 20 | 55813426 |
| 21 | 159047591 |
| 22 | 454373344 |
| 23 | 1301016216 |
| 24 | 3733009232 |
| 25 | 10731465131 |
| 26 | 30904208376 |
| 27 | 89140202911 |
| 28 | 257498974953 |
| 29 | 744861243809 |
| 30 | 2157405104355 |