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 | 3 |
| 2 | 13 |
| 3 | 49 |
| 4 | 161 |
| 5 | 481 |
| 6 | 1345 |
| 7 | 3585 |
| 8 | 9217 |
| 9 | 23041 |
| 10 | 56321 |
| 11 | 135169 |
| 12 | 319489 |
| 13 | 745473 |
| 14 | 1720321 |
| 15 | 3932161 |
| 16 | 8912897 |
| 17 | 20054017 |
| 18 | 44826625 |
| 19 | 99614721 |
| 20 | 220200961 |
| 21 | 484442113 |
| 22 | 1061158913 |
| 23 | 2315255809 |
| 24 | 5033164801 |
| 25 | 10905190401 |
| 26 | 23555211265 |
| 27 | 50734301185 |
| 28 | 108984795137 |