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 | 1 |
| 1 | 4 |
| 2 | 12 |
| 3 | 36 |
| 4 | 108 |
| 5 | 324 |
| 6 | 972 |
| 7 | 2916 |
| 8 | 8748 |
| 9 | 26244 |
| 10 | 78732 |
| 11 | 236196 |
| 12 | 708582 |
| 13 | 2125728 |
| 14 | 6377136 |
| 15 | 19131264 |
| 16 | 57393360 |
| 17 | 172178784 |
| 18 | 516532464 |
| 19 | 1549585728 |
| 20 | 4648722192 |
| 21 | 13946061600 |
| 22 | 41837869872 |
| 23 | 125512664832 |
| 24 | 376535160174 |
| 25 | 1129596977628 |