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 | 3 |
| 3 | 12 |
| 4 | 49 |
| 5 | 205 |
| 6 | 864 |
| 7 | 3653 |
| 8 | 15463 |
| 9 | 65484 |
| 10 | 277365 |
| 11 | 1174889 |
| 12 | 4976832 |
| 13 | 21082073 |
| 14 | 89304891 |
| 15 | 378301260 |
| 16 | 1602509321 |
| 17 | 6788337557 |
| 18 | 28755857952 |
| 19 | 121811766781 |
| 20 | 516002920895 |
| 21 | 2185823443596 |
| 22 | 9259296684333 |
| 23 | 39223010163217 |
| 24 | 166151337308544 |
| 25 | 703828359351025 |