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 | 0 |
| 1 | 18 |
| 2 | 18 |
| 3 | 36 |
| 4 | 54 |
| 5 | 90 |
| 6 | 144 |
| 7 | 234 |
| 8 | 378 |
| 9 | 612 |
| 10 | 990 |
| 11 | 1602 |
| 12 | 2592 |
| 13 | 4194 |
| 14 | 6786 |
| 15 | 10980 |
| 16 | 17766 |
| 17 | 28746 |
| 18 | 46512 |
| 19 | 75258 |
| 20 | 121770 |
| 21 | 197028 |
| 22 | 318798 |
| 23 | 515826 |
| 24 | 834624 |
| 25 | 1350450 |
| 26 | 2185074 |
| 27 | 3535524 |
| 28 | 5720598 |
| 29 | 9256122 |
| 30 | 14976720 |