[评论]数学趣题(60):偶数岛

东北汉

111    2466

Morning-guy

The expression they used is as follows:
for any natural number x, write
x=a_0+a_1*5 +a_2*5^2+...+a_n*5^n,
where 0<=a_0, a_1, a_2,...,a_n<5. Then they write x
as b_n...b_1b_0, where b_k=2*a_k.
So they write 111 as 842.

PolarBoy

222???