a(n+3) = 2^n - a(n), a(0)=a(2)=1, a(1)=0 for n >= 0.

Terms

a(0) =1a(1) =0a(2) =1a(3) =0a(4) =2a(5) =3a(6) =8a(7) =14a(8) =29a(9) =56a(10) =114a(11) =227a(12) =456a(13) =910a(14) =1821a(15) =3640a(16) =7282a(17) =14563a(18) =29128a(19) =58254a(20) =116509a(21) =233016a(22) =466034a(23) =932067a(24) =1864136a(25) =3728270a(26) =7456541a(27) =14913080a(28) =29826162a(29) =59652323