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 | 4 |
| 3 | 6 |
| 4 | 32 |
| 5 | 130 |
| 6 | 432 |
| 7 | 1274 |
| 8 | 3488 |
| 9 | 9090 |
| 10 | 22880 |
| 11 | 56122 |
| 12 | 134928 |
| 13 | 319202 |
| 14 | 745136 |
| 15 | 1719930 |
| 16 | 3931712 |
| 17 | 8912386 |
| 18 | 20053440 |
| 19 | 44825978 |
| 20 | 99614000 |
| 21 | 220200162 |
| 22 | 484441232 |
| 23 | 1061157946 |
| 24 | 2315254752 |
| 25 | 5033163650 |
| 26 | 10905189152 |
| 27 | 23555209914 |
| 28 | 50734299728 |
| 29 | 108984793570 |