a(n) = 5*a(n-1) - 2^n for n>0, a(0)=1.

Terms

a(0) =1a(1) =3a(2) =11a(3) =47a(4) =219a(5) =1063a(6) =5251a(7) =26127a(8) =130379a(9) =651383a(10) =3255891a(11) =16277407a(12) =81382939a(13) =406906503a(14) =2034516131a(15) =10172547887a(16) =50862673899a(17) =254313238423