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) |
|---|---|
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 1 |
| 8 | 2 |
| 9 | 5 |
| 10 | 12 |
| 11 | 34 |
| 12 | 130 |
| 13 | 525 |
| 14 | 2472 |
| 15 | 12400 |
| 16 | 65619 |
| 17 | 357504 |
| 18 | 1992985 |
| 19 | 11284042 |
| 20 | 64719885 |
| 21 | 375126827 |
| 22 | 2194439398 |
| 23 | 12941995397 |
| 24 | 76890024027 |
| 25 | 459873914230 |
| 26 | 2767364341936 |
| 27 | 16747182732792 |