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 | 16 |
| 5 | 223 |
| 6 | 2172 |
| 7 | 19451 |
| 8 | 175945 |
| 9 | 1569679 |
| 10 | 13954281 |
| 11 | 124059643 |
| 12 | 1105634145 |
| 13 | 9888091790 |
| 14 | 88792328084 |
| 15 | 800651549083 |
| 16 | 7249252855793 |
| 17 | 65896837322878 |
| 18 | 601279985076759 |