03/03/31 22:42
( 9 ^ 2 ) mod 21 == 18
( 9^3 ) mod 21
== ( (9^2) * 9 ) mod 21
== ( ( ( 9^2 ) mod 21 ) * ( 9 mod 21 ) ) mod 21
== ( 18 * 9 ) mod 21
== 15
( 9^4 ) mod 21
== ( (9^3) * 9 ) mod 21
== ( ( ( 9^3 ) mod 21 ) * ( 9 mod 21 ) ) mod 21
== ( 15 * 9 ) mod 21
== 9
( 9^5 ) mod 21
== ( (9^4) * 9 ) mod 21
== ( ( ( 9^4 ) mod 21 ) * ( 9 mod 21 ) ) mod 21
== ( 9 * 9 ) mod 21
== 18
以下同様に ( 9^47 ) mod 21 まで続ける。