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 | 1 |
| 4 | 3 |
| 5 | 12 |
| 6 | 50 |
| 7 | 240 |
| 8 | 1281 |
| 9 | 7588 |
| 10 | 49392 |
| 11 | 350775 |
| 12 | 2700115 |
| 13 | 22399476 |
| 14 | 199258488 |
| 15 | 1892343362 |
| 16 | 19111149225 |
| 17 | 204532683600 |
| 18 | 2312443695920 |
| 19 | 27541725738255 |
| 20 | 344681838284220 |
| 21 | 4522200516582650 |
| 22 | 62068382381998440 |
| 23 | 889492878311173290 |
| 24 | 13286058811968721515 |