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) |
|---|---|
| 1 | 0 |
| 2 | 2 |
| 3 | 4 |
| 4 | 18 |
| 5 | 80 |
| 6 | 154 |
| 7 | 684 |
| 8 | 3038 |
| 9 | 5848 |
| 10 | 25974 |
| 11 | 115364 |
| 12 | 222070 |
| 13 | 986328 |
| 14 | 4380794 |
| 15 | 8432812 |
| 16 | 37454490 |
| 17 | 166354808 |
| 18 | 320224786 |
| 19 | 1422284292 |
| 20 | 6317101910 |
| 21 | 12160109056 |
| 22 | 54009348606 |
| 23 | 239883517772 |
| 24 | 461763919342 |
| 25 | 2050932962736 |