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 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 13 |
| 5 | 57 |
| 6 | 265 |
| 7 | 1273 |
| 8 | 6281 |
| 9 | 31634 |
| 10 | 161985 |
| 11 | 840795 |
| 12 | 4413937 |
| 13 | 23395376 |
| 14 | 125028541 |
| 15 | 672958929 |
| 16 | 3644868105 |
| 17 | 19850452482 |
| 18 | 108639736105 |
| 19 | 597190462341 |
| 20 | 3295737021241 |
| 21 | 18253432801480 |
| 22 | 101425665527825 |
| 23 | 565249069709027 |
| 24 | 3158734991846065 |