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 | 1 |
| 2 | 2 |
| 3 | 9 |
| 4 | 18 |
| 5 | 1025 |
| 6 | 130 |
| 7 | 279937 |
| 8 | 65794 |
| 9 | 10078209 |
| 10 | 2097154 |
| 11 | 100000000001 |
| 12 | 16789506 |
| 13 | 106993205379073 |
| 14 | 156728328194 |
| 15 | 35185445863425 |
| 16 | 281479271743490 |
| 17 | 295147905179352825857 |
| 18 | 203119913861122 |
| 19 | 708235345355337676357633 |
| 20 | 1152923703631151106 |