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 | 9 |
| 3 | 33 |
| 4 | 165 |
| 5 | 1137 |
| 6 | 9837 |
| 7 | 95193 |
| 8 | 962541 |
| 9 | 9884889 |
| 10 | 102049197 |
| 11 | 1055383929 |
| 12 | 10921055661 |
| 13 | 113032307769 |
| 14 | 1169952636525 |
| 15 | 12109971475065 |
| 16 | 125349031354029 |
| 17 | 1297477519769145 |
| 18 | 13430093334225645 |
| 19 | 139013932289379321 |
| 20 | 1438923355509080877 |
| 21 | 14894194022848480185 |