The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 11 |
| 3 | 100 |
| 4 | 101 |
| 5 | 1000 |
| 6 | 1001 |
| 7 | 1011 |
| 8 | 1100 |
| 9 | 1101 |
| 10 | 1111 |
| 11 | -1 |
| 12 | -1 |
| 13 | -1 |
| 14 | -1 |
| 15 | -1 |
| 16 | 10000 |
| 17 | 10001 |
| 18 | 10011 |
| 19 | 10100 |
| 20 | 10101 |
| 21 | 11000 |
| 22 | 11001 |
| 23 | 11011 |
| 24 | 11100 |
| 25 | 11101 |
| 26 | 11111 |
| 27 | -1 |
| 28 | -1 |
| 29 | -1 |
| 30 | -1 |
| 31 | -1 |
| 32 | 100000 |
| 33 | 100001 |
| 34 | 100011 |
| 35 | 100100 |
| 36 | 100101 |
| 37 | 101000 |
| 38 | 101001 |
| 39 | 101011 |
| 40 | 101100 |
| 41 | 101101 |
| 42 | 101111 |
| 43 | -1 |
| 44 | -1 |
| 45 | -1 |
| 46 | -1 |
| 47 | -1 |
| 48 | 110000 |
| 49 | 110001 |
| 50 | 110011 |
[0,1,11,100,101,1000,1001,1011,1100,1101,1111,-1, -1,-1,-1,-1,10000,10001,10011,10100,10101,11000, 11001,11011,11100,11101,11111,-1,-1,-1,-1,-1, 100000,100001,100011,100100,100101,101000,101001, 101011,101100,101101,101111,-1,-1,-1,-1,-1,110000, 110001,110011] |