Sum of n-th Lucas number (A000032(n)) and n-th Pell number (A000129(n)).

Terms

a(0) =2a(1) =2a(2) =5a(3) =9a(4) =19a(5) =40a(6) =88a(7) =198a(8) =455a(9) =1061a(10) =2501a(11) =5940a(12) =14182a(13) =33982a(14) =81625a(15) =196389a(16) =473039a(17) =1140260a(18) =2749988a(19) =6634458a(20) =16009555a(21) =38638441a(22) =93261961a(23) =225122760a(24) =543443402a(25) =1311905882a(26) =3167087405a(27) =7645809249a(28) =18458266699a(29) =44561632000