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 | 1 |
| 2 | 4 |
| 3 | 13 |
| 4 | 44 |
| 5 | 149 |
| 6 | 504 |
| 7 | 1705 |
| 8 | 5768 |
| 9 | 19513 |
| 10 | 66012 |
| 11 | 223317 |
| 12 | 755476 |
| 13 | 2555757 |
| 14 | 8646064 |
| 15 | 29249425 |
| 16 | 98950096 |
| 17 | 334745777 |
| 18 | 1132436852 |
| 19 | 3831006429 |
| 20 | 12960201916 |
| 21 | 43844049029 |
| 22 | 148323355432 |
| 23 | 501774317241 |
| 24 | 1697490356184 |
| 25 | 5742568741225 |