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) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 0 |
| 3 | 1 |
| 4 | 6 |
| 5 | 12 |
| 6 | 11 |
| 7 | 30 |
| 8 | 120 |
| 9 | 252 |
| 10 | 408 |
| 11 | 1104 |
| 12 | 3415 |
| 13 | 7710 |
| 14 | 15984 |
| 15 | 42609 |
| 16 | 118422 |
| 17 | 281820 |
| 18 | 657468 |
| 19 | 1732008 |
| 20 | 4608288 |
| 21 | 11375240 |
| 22 | 28100400 |
| 23 | 73598112 |
| 24 | 192776895 |
| 25 | 487507038 |
| 26 | 1239516384 |
| 27 | 3241480275 |
| 28 | 8460205842 |
| 29 | 21733941060 |
| 30 | 56121723411 |
| 31 | 146904032622 |
| 32 | 383900676120 |