Number of palindromes of length n (in base 5).

Terms

a(0) =4a(1) =4a(2) =20a(3) =20a(4) =100a(5) =100a(6) =500a(7) =500a(8) =2500a(9) =2500a(10) =12500a(11) =12500a(12) =62500a(13) =62500a(14) =312500a(15) =312500a(16) =1562500a(17) =1562500a(18) =7812500a(19) =7812500a(20) =39062500a(21) =39062500a(22) =195312500a(23) =195312500a(24) =976562500a(25) =976562500a(26) =4882812500a(27) =4882812500a(28) =24414062500a(29) =24414062500