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 | -1 |
| 3 | 0 |
| 4 | 1 |
| 5 | 1 |
| 6 | 3 |
| 7 | 3 |
| 8 | 19 |
| 9 | 35 |
| 10 | 67 |
| 11 | 127 |
| 12 | 218 |
| 13 | 369 |
| 14 | 660 |
| 15 | 1267 |
| 16 | 2476 |
| 17 | 4863 |
| 18 | 9453 |
| 19 | 18078 |
| 20 | 34173 |
| 21 | 64374 |
| 22 | 121515 |
| 23 | 227965 |
| 24 | 426603 |
| 25 | 793638 |
| 26 | 1482307 |
| 27 | 2764957 |
| 28 | 5183333 |
| 29 | 9830514 |