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 | 2 |
| 5 | 6 |
| 6 | 23 |
| 7 | 109 |
| 8 | 618 |
| 9 | 4096 |
| 10 | 31133 |
| 11 | 267219 |
| 12 | 2557502 |
| 13 | 27011734 |
| 14 | 312115953 |
| 15 | 3916844779 |
| 16 | 53053052462 |
| 17 | 771450742596 |
| 18 | 11986779006647 |
| 19 | 198204672604489 |
| 20 | 3475110017769282 |
| 21 | 64396888392712366 |
| 22 | 1257612452945760503 |
| 23 | 25815617698822423341 |
| 24 | 555708180579477963962 |
| 25 | 12517189538209383465496 |