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 | 2 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 34 |
| 6 | 144 |
| 7 | 748 |
| 8 | 4606 |
| 9 | 32874 |
| 10 | 266968 |
| 11 | 2431612 |
| 12 | 24554190 |
| 13 | 272289634 |
| 14 | 3289836256 |
| 15 | 43017800316 |
| 16 | 605289111694 |
| 17 | 9119314568458 |
| 18 | 146474344313976 |
| 19 | 2498617856687404 |