16, as shown in the figure, the center of △ABC is on the Y axis, the coordinates of point C are (2,0), the coordinates of point B are (0,2), and the analytical formula of straight line AC is y= 12x- 1, so the value of tanA is 1/3.

Solution: According to the characteristics of triangular center, we know that ∠ABO=∠CBO,

Knowing the coordinates of point c and point b,

∴OB=OC，∠ OBC = 45，∠ ABC = 90。 It is known that △ABC is a right triangle and BC = 2 2.

∵ Point A is on the straight line AC, and the coordinate of point A is (x, 12x- 1).

According to the two-point distance formula:

AB2=x2+ ( 12x-3)2，

AC2 =(x-2)2+( 12x- 1)2，

In Rt△ABC,

AB2+BC2=AC2，

Solution: x=-6, y=-4,

∴ AB = 6 No.2,

∴tanA= BCAB= 2262= 13。

So the answer is: 13.