A=1+3¹+3²+3³+3⁴+3⁵+...+3¹¹⁴+3¹¹⁵+3¹¹⁶
A=1+3¹+3²+3³(1+3¹+3²)+...+3¹¹⁴(1+3¹+3²)
A=(1+3¹+3²)(3³+3⁶+...+3¹¹⁴)
A=(1+3+9)(3³+3⁶+...+3¹¹⁴)
A=13(3³+3⁶+...+3¹¹⁴) este divizibil cu 13
Kawaiimath
