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 | 4 |
| 2 | 4 |
| 3 | 20 |
| 4 | 32 |
| 5 | 80 |
| 6 | 180 |
| 7 | 408 |
| 8 | 940 |
| 9 | 2072 |
| 10 | 4824 |
| 11 | 10792 |
| 12 | 24660 |
| 13 | 55748 |
| 14 | 126760 |
| 15 | 287584 |
| 16 | 652280 |
| 17 | 1481184 |
| 18 | 3359900 |
| 19 | 7627296 |
| 20 | 17305472 |
| 21 | 39277688 |
| 22 | 89131928 |
| 23 | 202276640 |
| 24 | 459045772 |
| 25 | 1041743020 |
| 26 | 2364140452 |
| 27 | 5365103100 |
| 28 | 12175556108 |
| 29 | 27630957644 |
| 30 | 62705400664 |
| 31 | 142302685268 |