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) |
|---|---|
| 3 | 2 |
| 4 | 9 |
| 5 | 39 |
| 6 | 134 |
| 7 | 394 |
| 8 | 1040 |
| 9 | 2542 |
| 10 | 5876 |
| 11 | 13039 |
| 12 | 28080 |
| 13 | 59163 |
| 14 | 122694 |
| 15 | 251576 |
| 16 | 511720 |
| 17 | 1035068 |
| 18 | 2085640 |
| 19 | 4191629 |
| 20 | 8409592 |
| 21 | 16852833 |
| 22 | 33748170 |
| 23 | 67549470 |
| 24 | 135164720 |
| 25 | 270410170 |
| 26 | 540918620 |
| 27 | 1081955995 |
| 28 | 2164054496 |