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) |
|---|---|
| 3 | 1 |
| 4 | 9 |
| 5 | 41 |
| 6 | 146 |
| 7 | 456 |
| 8 | 1312 |
| 9 | 3568 |
| 10 | 9312 |
| 11 | 23552 |
| 12 | 58112 |
| 13 | 140544 |
| 14 | 334336 |
| 15 | 784384 |
| 16 | 1818624 |
| 17 | 4173824 |
| 18 | 9494528 |
| 19 | 21430272 |
| 20 | 48037888 |
| 21 | 107020288 |
| 22 | 237109248 |
| 23 | 522715136 |
| 24 | 1147142144 |
| 25 | 2507145216 |
| 26 | 5458886656 |
| 27 | 11844714496 |
| 28 | 25618808832 |
| 29 | 55247372288 |