Question

Find the number of positive integers n less than 1000 such that 20^n - 13^n - 7^n is divisible by 309

Answer 1

I'll give you a hint:\[20^{6}\stackrel{103}{\equiv} 23\]\[13^{6}\stackrel{103}{\equiv} 23\]\[7^{6}\stackrel{103}{\equiv} 23\]

Answer 2

don't you love it when a question gets posted and they just disappear!

Answer 3

What is the symbol did u use with 103 and 3 lines under it and looks that is unfamiliar to me, @mukushla :)

Answer 4

@tanjung i believe the 3 lines is the "equivalence" symbol

http://www.rapidtables.com/math/symbols/Basic_Math_Symbols.htm#algebra

Answer 5

Ok thanks jack, i know the 3 lines is equivalence symbol but i never seen there is a number above that lines

Answer 6

So, the answer is n = 6 ? Only one possible of n ?