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 | 1 |
| 5 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 1 |
| 9 | 5 |
| 10 | 15 |
| 11 | 35 |
| 12 | 71 |
| 13 | 131 |
| 14 | 230 |
| 15 | 395 |
| 16 | 686 |
| 17 | 1231 |
| 18 | 2316 |
| 19 | 4565 |
| 20 | 9326 |
| 21 | 19466 |
| 22 | 41002 |
| 23 | 86401 |
| 24 | 181231 |
| 25 | 377441 |
| 26 | 779797 |
| 27 | 1598263 |
| 28 | 3251522 |
| 29 | 6571171 |
| 30 | 13204057 |
| 31 | 26404654 |
| 32 | 52595856 |
| 33 | 104445292 |
| 34 | 206934917 |
| 35 | 409352089 |
| 36 | 809015298 |
| 37 | 1598295894 |
| 38 | 3157969548 |
| 39 | 6242861979 |