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 | 3 |
| 2 | 9 |
| 3 | 21 |
| 4 | 45 |
| 5 | 92 |
| 6 | 177 |
| 7 | 351 |
| 8 | 702 |
| 9 | 1379 |
| 10 | 2724 |
| 11 | 5412 |
| 12 | 10787 |
| 13 | 21502 |
| 14 | 42958 |
| 15 | 85791 |
| 16 | 171441 |
| 17 | 342216 |
| 18 | 683462 |
| 19 | 1365580 |
| 20 | 2729447 |
| 21 | 5456194 |
| 22 | 10908253 |
| 23 | 21812343 |
| 24 | 43616683 |
| 25 | 87223016 |
| 26 | 174430392 |