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 | 9 |
| 2 | 81 |
| 3 | 323 |
| 4 | 1360 |
| 5 | 6525 |
| 6 | 32393 |
| 7 | 165626 |
| 8 | 855471 |
| 9 | 4449491 |
| 10 | 23211486 |
| 11 | 121314285 |
| 12 | 634633939 |
| 13 | 3321850282 |
| 14 | 17392770603 |
| 15 | 91082814851 |
| 16 | 477033173168 |
| 17 | 2498544485965 |
| 18 | 13087020633451 |
| 19 | 68549369291830 |
| 20 | 359063591740895 |
| 21 | 1880798904630019 |