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 | -2 |
| 1 | -1 |
| 2 | 4 |
| 3 | 20 |
| 4 | 64 |
| 5 | 176 |
| 6 | 448 |
| 7 | 1088 |
| 8 | 2560 |
| 9 | 5888 |
| 10 | 13312 |
| 11 | 29696 |
| 12 | 65536 |
| 13 | 143360 |
| 14 | 311296 |
| 15 | 671744 |
| 16 | 1441792 |
| 17 | 3080192 |
| 18 | 6553600 |
| 19 | 13893632 |
| 20 | 29360128 |
| 21 | 61865984 |
| 22 | 130023424 |
| 23 | 272629760 |
| 24 | 570425344 |
| 25 | 1191182336 |
| 26 | 2483027968 |
| 27 | 5167382528 |
| 28 | 10737418240 |