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 | 0 |
| 2 | 6 |
| 3 | 0 |
| 4 | 28 |
| 5 | 0 |
| 6 | 120 |
| 7 | 0 |
| 8 | 496 |
| 9 | 0 |
| 10 | 2016 |
| 11 | 0 |
| 12 | 8128 |
| 13 | 0 |
| 14 | 32640 |
| 15 | 0 |
| 16 | 130816 |
| 17 | 0 |
| 18 | 523776 |
| 19 | 0 |
| 20 | 2096128 |
| 21 | 0 |
| 22 | 8386560 |
| 23 | 0 |
| 24 | 33550336 |
| 25 | 0 |
| 26 | 134209536 |
| 27 | 0 |
| 28 | 536854528 |
| 29 | 0 |
| 30 | 2147450880 |
| 31 | 0 |
| 32 | 8589869056 |
| 33 | 0 |
| 34 | 34359607296 |
| 35 | 0 |
| 36 | 137438691328 |
| 37 | 0 |
| 38 | 549755289600 |
| 39 | 0 |
| 40 | 2199022206976 |
| 41 | 0 |