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 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 2 |
| 6 | 1 |
| 7 | 6 |
| 8 | 12 |
| 9 | 46 |
| 10 | 92 |
| 11 | 341 |
| 12 | 1787 |
| 13 | 9233 |
| 14 | 45752 |
| 15 | 285053 |
| 16 | 1846955 |
| 17 | 11977939 |
| 18 | 83263591 |
| 19 | 621012754 |
| 20 | 4878666808 |
| 21 | 39333324973 |
| 22 | 336376244042 |
| 23 | 3029242658210 |
| 24 | 28439272956934 |
| 25 | 275986683743434 |
| 26 | 2789712466510289 |
| 27 | 29363495934315694 |