Sum of Fibonacci (A000045) and Pell (A000129) numbers.

Terms

a(0) =0a(1) =2a(2) =3a(3) =7a(4) =15a(5) =34a(6) =78a(7) =182a(8) =429a(9) =1019a(10) =2433a(11) =5830a(12) =14004a(13) =33694a(14) =81159a(15) =195635a(16) =471819a(17) =1138286a(18) =2746794a(19) =6629290a(20) =16001193a(21) =38624911a(22) =93240069a(23) =225087338a(24) =543386088a(25) =1311813146a(26) =3166937355a(27) =7645566463a(28) =18457873863a(29) =44560996378