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 | 2 |
| 5 | 15 |
| 6 | 60 |
| 7 | 469 |
| 8 | 3660 |
| 9 | 32958 |
| 10 | 328920 |
| 11 | 3614490 |
| 12 | 43341822 |
| 13 | 563144725 |
| 14 | 7880897892 |
| 15 | 118177520295 |
| 16 | 1890389939000 |
| 17 | 32130521850972 |
| 18 | 578260307815920 |
| 19 | 10985555094348948 |
| 20 | 219687969344126490 |
| 21 | 4613039009310624795 |
| 22 | 101479234383619208204 |
| 23 | 2333872309936442446905 |