a(n) + a(n+1) = 2^n for n >= 0 with a(0) = 4.

Terms

a(0) =4a(1) =-3a(2) =5a(3) =-1a(4) =9a(5) =7a(6) =25a(7) =39a(8) =89a(9) =167a(10) =345a(11) =679a(12) =1369a(13) =2727a(14) =5465a(15) =10919a(16) =21849a(17) =43687a(18) =87385a(19) =174759a(20) =349529a(21) =699047a(22) =1398105a(23) =2796199a(24) =5592409a(25) =11184807a(26) =22369625a(27) =44739239a(28) =89478489a(29) =178956967