[填空题]
The barcode strings of a new product are created from four letterfn:a4fz/ki u k.00s r0nii2gs -pe e a6ega uyt58n(e8s $ \mathrm{A}$, $\mathrm{B}$, $\mathrm{C}$, $\mathrm{D}$ and ten digits $0,1,2, \ldots, 9$ . No three of the letters may be written consecutively in a barcode string. There is no restriction on the order in which the numbers can be written. Find the number of different barcode strings that can be created.$\approx a \times 10^{b}$ a = b =
