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 | 948 |
| 7 | 2772 |
| 8 | 8076 |
| 9 | 23508 |
| 10 | 67980 |
| 11 | 196548 |
| 12 | 566820 |
| 13 | 1633956 |
| 14 | 4697412 |
| 15 | 13501492 |
| 16 | 38742652 |
| 17 | 111146820 |
| 18 | 318390684 |
| 19 | 911904996 |
| 20 | 2608952940 |
| 21 | 7463042916 |
| 22 | 21328259716 |