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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 13 |
| 6 | 115 |
| 7 | 959 |
| 8 | 8876 |
| 9 | 101123 |
| 10 | 1519504 |
| 11 | 31138405 |
| 12 | 871560677 |
| 13 | 32897263307 |
| 14 | 1657411773700 |
| 15 | 111113100638331 |
| 16 | 9929019852558612 |
| 17 | 1185818207579540160 |
| 18 | 189496976724420953109 |
| 19 | 40497113442395855810240 |
| 20 | 11561238705271610991734848 |