Răspuns :
[tex] 2^{n} + 2^{n+1} +3*2 ^{n+2} +7* 2^{n+3} =2 ^{n} (1+2+3*2^2+7*2^3)= \\ \\ =2^n(3+3*4+7*8)=2^n(3+12+56)=2^n *71 se /divide / cu / 71[/tex]
a = 2 ⁿ + 2 ⁿ ⁺ ¹ + 3 x 2 ⁿ⁺² + 7 x 2ⁿ⁺³ l cu 71
a = 2 ⁿ( 1 + 2¹ + 3 x 2² + 7 x 2³ )
a = 2 ⁿ ( 3 + 3 x 4 + 7 x 8 )
a = 2 ⁿ ( 15 + 56 )
a = 2 ⁿ x 71 l cu 71
a = 2 ⁿ( 1 + 2¹ + 3 x 2² + 7 x 2³ )
a = 2 ⁿ ( 3 + 3 x 4 + 7 x 8 )
a = 2 ⁿ ( 15 + 56 )
a = 2 ⁿ x 71 l cu 71