a(n) = (n+1)*Fibonacci(n+2) + 3.

Terms

a(0) =4a(1) =7a(2) =12a(3) =23a(4) =43a(5) =81a(6) =150a(7) =275a(8) =498a(9) =893a(10) =1587a(11) =2799a(12) =4904a(13) =8543a(14) =14808a(15) =25555a(16) =43931a(17) =75261a(18) =128538a(19) =218923a(20) =371934a(21) =630457a(22) =1066467a(23) =1800603a(24) =3034828a(25) =5106871a(26) =8580900a(27) =14398415a(28) =24129163a(29) =40388073