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 | 1 |
| 4 | 1 |
| 5 | 2 |
| 6 | 5 |
| 7 | 12 |
| 8 | 31 |
| 9 | 90 |
| 10 | 285 |
| 11 | 938 |
| 12 | 3285 |
| 13 | 11983 |
| 14 | 45390 |
| 15 | 177803 |
| 16 | 718390 |
| 17 | 2986407 |
| 18 | 12749364 |
| 19 | 55802982 |
| 20 | 250068732 |
| 21 | 1145923828 |
| 22 | 5363795830 |
| 23 | 25620207380 |
| 24 | 124767647097 |
| 25 | 618983876918 |
| 26 | 3126035142910 |
| 27 | 16060182735947 |
| 28 | 83883575376862 |
| 29 | 445164927249466 |
| 30 | 2399098651337048 |