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 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 30 |
| 5 | 81 |
| 6 | 270 |
| 7 | 729 |
| 8 | 2269 |
| 9 | 6597 |
| 10 | 19926 |
| 11 | 59049 |
| 12 | 178146 |
| 13 | 531441 |
| 14 | 1596510 |
| 15 | 4783698 |
| 16 | 14355900 |
| 17 | 43046721 |
| 18 | 129162141 |
| 19 | 387420489 |
| 20 | 1162322946 |
| 21 | 3486790962 |
| 22 | 10460530350 |
| 23 | 31381059609 |
| 24 | 94143737979 |
| 25 | 282429539721 |
| 26 | 847290203766 |
| 27 | 2541865887462 |
| 28 | 7625602289826 |
| 29 | 22876792454961 |
| 30 | 68630391912807 |