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 | 2 |
| 2 | 4 |
| 3 | 14 |
| 4 | 52 |
| 5 | 214 |
| 6 | 916 |
| 7 | 4116 |
| 8 | 18996 |
| 9 | 89894 |
| 10 | 433196 |
| 11 | 2119904 |
| 12 | 10503612 |
| 13 | 52594476 |
| 14 | 265713532 |
| 15 | 1352796790 |
| 16 | 6933598208 |
| 17 | 35747017596 |
| 18 | 185260197772 |
| 19 | 964585369012 |
| 20 | 5043220350012 |
| 21 | 26467146038744 |
| 22 | 139375369621960 |
| 23 | 736229024863276 |
| 24 | 3900074570513316 |
| 25 | 20714056652990194 |