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) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 8 |
| 7 | 32 |
| 8 | 101 |
| 9 | 687 |
| 10 | 3584 |
| 11 | 23564 |
| 12 | 146424 |
| 13 | 937953 |
| 14 | 6006835 |
| 15 | 38521889 |
| 16 | 247868209 |
| 17 | 1591813628 |
| 18 | 10234693956 |
| 19 | 65662254277 |
| 20 | 420757890998 |
| 21 | 2688786485779 |
| 22 | 17134894394402 |
| 23 | 108819902923649 |
| 24 | 688544716659489 |
| 25 | 4339161392334630 |
| 26 | 27229261402800035 |
| 27 | 170114849290565556 |