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 | 576 |
| 4 | 3969 |
| 5 | 25281 |
| 6 | 155236 |
| 7 | 915849 |
| 8 | 5253264 |
| 9 | 29365561 |
| 10 | 160731684 |
| 11 | 863478225 |
| 12 | 4564353600 |
| 13 | 23782266225 |
| 14 | 122339052900 |
| 15 | 622112365081 |
| 16 | 3130733894544 |
| 17 | 15606442349001 |
| 18 | 77125175024836 |
| 19 | 378120197667969 |
| 20 | 1840241149473024 |