2^3+2^2-2^1 ... 2^3+2^2-2^1-2^0 ... 2^3 ... 2^6-2^5-2^4-2^3-2^1-2^0 ... 2^8-2^7-2^6-2^5-2^4-2^3-2^1 ... 2^7-2^6-2^5-2^4-2^3-2^0 ... 2^7-2^6-2^5-2^4-2^3-2^2 ... 2^7-2^6-2^5-2^4-2^3-2^2-2^0 ... 2^5-2^4-2^3-2^2-2^1 ... 2^7-2^6-2^5-2^4-2^3-2^2-2^1-2^0 ... ?