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 | 281 |
| 4 | 989 |
| 5 | 3923 |
| 6 | 15921 |
| 7 | 67007 |
| 8 | 286299 |
| 9 | 1240603 |
| 10 | 5420023 |
| 11 | 23828357 |
| 12 | 105188575 |
| 13 | 465711669 |
| 14 | 2065999789 |
| 15 | 9177987717 |
| 16 | 40811215453 |
| 17 | 181593070243 |
| 18 | 808383490865 |
| 19 | 3599754765767 |
| 20 | 16033313059243 |
| 21 | 71423194026691 |
| 22 | 318200352273815 |