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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 2 |
| 4 | 2 |
| 5 | 6 |
| 6 | 6 |
| 7 | 14 |
| 8 | 14 |
| 9 | 30 |
| 10 | 30 |
| 11 | 62 |
| 12 | 62 |
| 13 | 126 |
| 14 | 126 |
| 15 | 254 |
| 16 | 254 |
| 17 | 510 |
| 18 | 510 |
| 19 | 1022 |
| 20 | 1022 |
| 21 | 2046 |
| 22 | 2046 |
| 23 | 4094 |
| 24 | 4094 |
| 25 | 8190 |
| 26 | 8190 |
| 27 | 16382 |
| 28 | 16382 |
| 29 | 32766 |
| 30 | 32766 |
| 31 | 65534 |
| 32 | 65534 |
| 33 | 131070 |
| 34 | 131070 |
| 35 | 262142 |
| 36 | 262142 |
| 37 | 524286 |
| 38 | 524286 |
| 39 | 1048574 |
| 40 | 1048574 |
| 41 | 2097150 |
| 42 | 2097150 |
| 43 | 4194302 |