a(n) = 2^n*(1-n).

Terms

a(0) =1a(1) =0a(2) =-4a(3) =-16a(4) =-48a(5) =-128a(6) =-320a(7) =-768a(8) =-1792a(9) =-4096a(10) =-9216a(11) =-20480a(12) =-45056a(13) =-98304a(14) =-212992a(15) =-458752a(16) =-983040a(17) =-2097152a(18) =-4456448a(19) =-9437184a(20) =-19922944a(21) =-41943040a(22) =-88080384a(23) =-184549376a(24) =-385875968a(25) =-805306368a(26) =-1677721600a(27) =-3489660928