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) |
|---|---|
| 3 | 1 |
| 4 | 2 |
| 5 | 6 |
| 6 | 25 |
| 7 | 107 |
| 8 | 509 |
| 9 | 2468 |
| 10 | 12258 |
| 11 | 61797 |
| 12 | 315830 |
| 13 | 1630770 |
| 14 | 8498303 |
| 15 | 44629855 |
| 16 | 235974495 |
| 17 | 1255105304 |
| 18 | 6710883952 |
| 19 | 36050676617 |
| 20 | 194478962422 |
| 21 | 1053120661726 |
| 22 | 5722375202661 |
| 23 | 31191334491891 |
| 24 | 170504130213135 |
| 25 | 934495666529380 |
| 26 | 5134182220623958 |
| 27 | 28270742653671621 |