a(0)=1, a(1)=2; for n>1, a(n)=3*a(n-1)+4*a(n-2)+5.

Terms

a(0) =1a(1) =2a(2) =15a(3) =58a(4) =239a(5) =954a(6) =3823a(7) =15290a(8) =61167a(9) =244666a(10) =978671a(11) =3914682a(12) =15658735a(13) =62634938a(14) =250539759a(15) =1002159034a(16) =4008636143a(17) =16034544570a(18) =64138178287a(19) =256552713146