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 | 18 |
| 1 | 90 |
| 2 | 270 |
| 3 | 666 |
| 4 | 1494 |
| 5 | 3186 |
| 6 | 6606 |
| 7 | 13482 |
| 8 | 27270 |
| 9 | 54882 |
| 10 | 110142 |
| 11 | 220698 |
| 12 | 441846 |
| 13 | 884178 |
| 14 | 1768878 |
| 15 | 3538314 |
| 16 | 7077222 |
| 17 | 14155074 |
| 18 | 28310814 |
| 19 | 56622330 |
| 20 | 113245398 |
| 21 | 226491570 |
| 22 | 452983950 |
| 23 | 905968746 |
| 24 | 1811938374 |
| 25 | 3623877666 |
| 26 | 7247756286 |
| 27 | 14495513562 |
| 28 | 28991028150 |