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) |
|---|---|
| 2 | 1 |
| 3 | 7 |
| 4 | 37 |
| 5 | 177 |
| 6 | 809 |
| 7 | 3614 |
| 8 | 15959 |
| 9 | 70101 |
| 10 | 307442 |
| 11 | 1349374 |
| 12 | 5935806 |
| 13 | 26195458 |
| 14 | 116049130 |
| 15 | 516291384 |
| 16 | 2307167923 |
| 17 | 10357044612 |
| 18 | 46705335181 |
| 19 | 211564961875 |
| 20 | 962540059715 |
| 21 | 4397719306200 |
| 22 | 20174135878046 |
| 23 | 92905048669662 |
| 24 | 429412711250262 |