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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 5 |
| 4 | 22 |
| 5 | 97 |
| 6 | 408 |
| 7 | 1752 |
| 8 | 7535 |
| 9 | 32895 |
| 10 | 144816 |
| 11 | 644058 |
| 12 | 2886967 |
| 13 | 13037352 |
| 14 | 59248959 |
| 15 | 270799903 |
| 16 | 1243939278 |
| 17 | 5740014143 |
| 18 | 26594306442 |
| 19 | 123668622726 |
| 20 | 577003771681 |
| 21 | 2700346810482 |
| 22 | 12672753684799 |
| 23 | 59625966523555 |
| 24 | 281207237408728 |
| 25 | 1329130156859362 |