Răspuns:
Explicație pas cu pas:
3=M₄+3 (multiplu de 4+...)
3²=M₄+1
3³=M₄+3
3⁴=M₄+1
................
3²⁰⁰³=M₄+3
3²⁰⁰⁴=M₄+1
C=(M₄+3)+(M₄+1)+...+(M₄+3)+(M₄+1)=M₄
Sau altfel:
C = 3*(1+3)+3³*(1+3)+...3²⁰⁰³*(1+3)= 4* (3¹+3³+...+3²⁰⁰³) = M₄
D = (7¹+7²+7³)+(7⁴+7⁵+7⁶)+...+(7²⁰⁰²+7²⁰⁰³+7²⁰⁰⁴)=
= 7*(1+7+7²)+7⁴(1+7+7²)+...+7²⁰⁰²(1+7+7²) = (1+7+7²)*(7+7⁴+...+7²⁰⁰²) =
= 57* (7+7⁴+...+7²⁰⁰²) = M₅₇
