13
p congruent to 3(mod 4)
given 4|(p-3)
or, p-3=4k
or, p=4k+3 k is in set of integers
or, p-1=4k+2=2(2k+1) which is given equation
by fermat's theorem
2^{p-1}4^{p-1}6^{p-1}....(p-1)^{p-1}is congruent to 1(mod p)
or, {(2)(4)(6)....(p-1)}^{p-1}is congruent to 1(modp)
or,{(2)(4)(6).....(p-1)} is congruent to 1^{\frac{1}{p-1}}(modp)
or, {(2)(4)(6)....(p-1)} is congruent to 1^{\frac{1}{2(2k+1)}(mod p)
or, {(2)(4)(6)....(p-1)} is congruent to =+-1(modp)
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