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 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 1 |
| 8 | 0 |
| 9 | 20 |
| 10 | 103 |
| 11 | 594 |
| 12 | 1192 |
| 13 | 6290 |
| 14 | 18099 |
| 15 | 54808 |
| 16 | 159048 |
| 17 | 502366 |
| 18 | 1374593 |
| 19 | 4076218 |
| 20 | 11378831 |
| 21 | 32674779 |
| 22 | 93006494 |
| 23 | 264720498 |
| 24 | 748062099 |
| 25 | 2134512296 |
| 26 | 6071524897 |
| 27 | 17289205132 |
| 28 | 49268564671 |
| 29 | 140605019208 |
| 30 | 401392287316 |