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 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 26 |
| 6 | 74 |
| 7 | 218 |
| 8 | 668 |
| 9 | 2116 |
| 10 | 6928 |
| 11 | 23254 |
| 12 | 79998 |
| 13 | 281694 |
| 14 | 1011956 |
| 15 | 3704900 |
| 16 | 13815692 |
| 17 | 52386978 |
| 18 | 201787950 |
| 19 | 789178950 |
| 20 | 3130824160 |
| 21 | 12589367840 |
| 22 | 51287685476 |
| 23 | 211557376938 |
| 24 | 883067740514 |
| 25 | 3728494418330 |
| 26 | 15916998678040 |
| 27 | 68672820917088 |
| 28 | 299331260431104 |