a(n) = F(n)*L(n+2) where F=Fibonacci and L=Lucas numbers.

Terms

a(0) =0a(1) =4a(2) =7a(3) =22a(4) =54a(5) =145a(6) =376a(7) =988a(8) =2583a(9) =6766a(10) =17710a(11) =46369a(12) =121392a(13) =317812a(14) =832039a(15) =2178310a(16) =5702886a(17) =14930353a(18) =39088168a(19) =102334156a(20) =267914295a(21) =701408734a(22) =1836311902a(23) =4807526977a(24) =12586269024a(25) =32951280100a(26) =86267571271a(27) =225851433718a(28) =591286729878