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 | 13 |
| 2 | 59 |
| 3 | 217 |
| 4 | 927 |
| 5 | 4003 |
| 6 | 17735 |
| 7 | 79603 |
| 8 | 361207 |
| 9 | 1652347 |
| 10 | 7608009 |
| 11 | 35214643 |
| 12 | 163703859 |
| 13 | 763777807 |
| 14 | 3574392251 |
| 15 | 16771283857 |
| 16 | 78867271271 |
| 17 | 371585266531 |
| 18 | 1753627967177 |
| 19 | 8287756490659 |
| 20 | 39216985201477 |
| 21 | 185770958749075 |