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 | 3 |
| 1 | 18 |
| 2 | 108 |
| 3 | 648 |
| 4 | 3888 |
| 5 | 23328 |
| 6 | 139968 |
| 7 | 839808 |
| 8 | 5038848 |
| 9 | 30233088 |
| 10 | 181398528 |
| 11 | 1088391168 |
| 12 | 6530347008 |
| 13 | 39182082048 |
| 14 | 235092492288 |
| 15 | 1410554953728 |
| 16 | 8463329722368 |
| 17 | 50779978334208 |
| 18 | 304679870005248 |
| 19 | 1828079220031488 |
| 20 | 10968475320188928 |
| 21 | 65810851921133568 |
| 22 | 394865111526801408 |