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 | 15 |
| 3 | 49 |
| 4 | 143 |
| 5 | 406 |
| 6 | 1174 |
| 7 | 3507 |
| 8 | 10674 |
| 9 | 32965 |
| 10 | 102716 |
| 11 | 321797 |
| 12 | 1011533 |
| 13 | 3186389 |
| 14 | 10050743 |
| 15 | 31730134 |
| 16 | 100228040 |
| 17 | 316713623 |
| 18 | 1001037546 |
| 19 | 3164497349 |
| 20 | 10004755374 |
| 21 | 31632975598 |
| 22 | 100021893194 |
| 23 | 316274794666 |
| 24 | 1000101078148 |
| 25 | 3162495003352 |
| 26 | 10000467510247 |
| 27 | 31623782520064 |
| 28 | 100002164895587 |