Number of palindromes of length n (in base 4).

Terms

a(0) =3a(1) =3a(2) =12a(3) =12a(4) =48a(5) =48a(6) =192a(7) =192a(8) =768a(9) =768a(10) =3072a(11) =3072a(12) =12288a(13) =12288a(14) =49152a(15) =49152a(16) =196608a(17) =196608a(18) =786432a(19) =786432a(20) =3145728a(21) =3145728a(22) =12582912a(23) =12582912a(24) =50331648a(25) =50331648a(26) =201326592a(27) =201326592a(28) =805306368a(29) =805306368