Number of length-n binary strings that are the concatenation of two nonempty palindromes.

Terms

a(0) =0a(1) =4a(2) =6a(3) =14a(4) =26a(5) =48a(6) =86a(7) =148a(8) =232a(9) =400a(10) =622a(11) =982a(12) =1514a(13) =2440a(14) =3482a(15) =5680a(16) =8162a(17) =12932a(18) =18398a(19) =29146a(20) =40706a(21) =64856a(22) =90070a(23) =141880a(24) =196448a(25) =309712a(26) =425412a(27) =668978a(28) =917450a(29) =1437148