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 | 4 |
| 2 | 17 |
| 3 | 58 |
| 4 | 199 |
| 5 | 682 |
| 6 | 2301 |
| 7 | 7654 |
| 8 | 25145 |
| 9 | 81740 |
| 10 | 263407 |
| 11 | 842720 |
| 12 | 2679935 |
| 13 | 8479378 |
| 14 | 26713555 |
| 15 | 83847748 |
| 16 | 262335577 |
| 17 | 818473148 |
| 18 | 2547289679 |
| 19 | 7910433568 |
| 20 | 24517303535 |
| 21 | 75854736178 |
| 22 | 234317624167 |
| 23 | 722776320072 |
| 24 | 2226565995913 |