A=(2^2+2^4)+2^4(2^2+2^4) +.........2^26(2^2+2^4)
A=(2^2+2^4)[1+2^4+................2^26)]
A=20 x M ⇒ 20|A
A=(1+5^2)+5^4(1+5^2)+............5^32(1+5^2)
A=26(1+5^4+5^4+5^8+.....5^32)
26|A
A=(7+7^2+7^3+7^4)+7^4(7+7^2+7^3+7^4)+.......7^96(7+7^2+7^3+7^4)
A=2800(1+7^4+7^8+........7^96)
50|A
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