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 | 369 |
| 4 | 2241 |
| 5 | 12609 |
| 6 | 73089 |
| 7 | 419841 |
| 8 | 2419713 |
| 9 | 13930497 |
| 10 | 80230401 |
| 11 | 462012417 |
| 12 | 2660655105 |
| 13 | 15322038273 |
| 14 | 88236228609 |
| 15 | 508131934209 |
| 16 | 2926215692289 |
| 17 | 16851403538433 |
| 18 | 97043367329793 |
| 19 | 558850475294721 |
| 20 | 3218291629752321 |