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 | 6 |
| 2 | 20 |
| 3 | 62 |
| 4 | 188 |
| 5 | 566 |
| 6 | 1700 |
| 7 | 5102 |
| 8 | 15308 |
| 9 | 45926 |
| 10 | 137780 |
| 11 | 413342 |
| 12 | 1240028 |
| 13 | 3720086 |
| 14 | 11160260 |
| 15 | 33480782 |
| 16 | 100442348 |
| 17 | 301327046 |
| 18 | 903981140 |
| 19 | 2711943422 |
| 20 | 8135830268 |
| 21 | 24407490806 |
| 22 | 73222472420 |
| 23 | 219667417262 |
| 24 | 659002251788 |