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 | 2 |
| 2 | 8 |
| 3 | 36 |
| 4 | 170 |
| 5 | 826 |
| 6 | 4088 |
| 7 | 20496 |
| 8 | 103752 |
| 9 | 529100 |
| 10 | 2714140 |
| 11 | 13989560 |
| 12 | 72393412 |
| 13 | 375877684 |
| 14 | 1957199120 |
| 15 | 10216355632 |
| 16 | 53443289946 |
| 17 | 280101010170 |
| 18 | 1470508417340 |
| 19 | 7731675774900 |
| 20 | 40706787482130 |
| 21 | 214580612067690 |
| 22 | 1132389348358320 |
| 23 | 5981916549623040 |
| 24 | 31629125981208600 |