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 | 2 |
| 3 | 3 |
| 4 | 13 |
| 5 | 32 |
| 6 | 121 |
| 7 | 376 |
| 8 | 1406 |
| 9 | 5030 |
| 10 | 19632 |
| 11 | 76334 |
| 12 | 314582 |
| 13 | 1308550 |
| 14 | 5667494 |
| 15 | 24940458 |
| 16 | 113239394 |
| 17 | 523149560 |
| 18 | 2480434938 |
| 19 | 11968944532 |
| 20 | 59051754824 |