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) |
|---|---|
| 0 | 6 |
| 1 | 21 |
| 2 | 81 |
| 3 | 321 |
| 4 | 1281 |
| 5 | 5121 |
| 6 | 20481 |
| 7 | 81921 |
| 8 | 327681 |
| 9 | 1310721 |
| 10 | 5242881 |
| 11 | 20971521 |
| 12 | 83886081 |
| 13 | 335544321 |
| 14 | 1342177281 |
| 15 | 5368709121 |
| 16 | 21474836481 |
| 17 | 85899345921 |
| 18 | 343597383681 |
| 19 | 1374389534721 |
| 20 | 5497558138881 |
| 21 | 21990232555521 |
| 22 | 87960930222081 |