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 | 1 |
| 5 | 2 |
| 6 | 4 |
| 7 | 11 |
| 8 | 20 |
| 9 | 40 |
| 10 | 109 |
| 11 | 198 |
| 12 | 396 |
| 13 | 1079 |
| 14 | 1960 |
| 15 | 3920 |
| 16 | 10681 |
| 17 | 19402 |
| 18 | 38804 |
| 19 | 105731 |
| 20 | 192060 |
| 21 | 384120 |
| 22 | 1046629 |
| 23 | 1901198 |
| 24 | 3802396 |
| 25 | 10360559 |
| 26 | 18819920 |
| 27 | 37639840 |
| 28 | 102558961 |
| 29 | 186298002 |