The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 111 |
| 3 | 0 |
| 4 | 11111 |
| 5 | 0 |
| 6 | 1111111 |
| 7 | 0 |
| 8 | 111111111 |
| 9 | 0 |
| 10 | 11111111111 |
| 11 | 0 |
| 12 | 1111111111111 |
| 13 | 1100000000 |
| 14 | 111111111111111 |
| 15 | 11111100000000 |
| 16 | 11100001111111111 |
| 17 | 11001100000000 |
| 18 | 1111110111111111111 |
| 19 | 1111111100000000 |
| 20 | 111110000001111111111 |
| 21 | 1111000000000000 |
[1,0,111,0,11111,0,1111111,0,111111111,0, 11111111111,0,1111111111111,1100000000, 111111111111111,11111100000000,11100001111111111, 11001100000000,1111110111111111111, 1111111100000000,111110000001111111111, 1111000000000000] |