A358257 - OEIS

%I #19 Dec 25 2022 15:04:36

%S 0,5,5,8,8,8,1,1,1,4,4,4,7,7,7,0,0,0,3,3,3,6,6,6,9,9,2,2,2,5,5,5,8,8,

%T 8,1,1,1,4,4,4,7,7,7,0,0,0,3,3,3,6,6,6,9,9,9,2,2,2,5,5,5,8,8,8,1,1,1,

%U 4,4,4,7,7,7,0,0,0,3,3,3,6,6,6,9,9,9,2,2,2,5,5,8,8,8,1,1,1,4,4,4,7,7,7,0,0

%N The least significant digit of k such that 2^k, 5^k, 8^k start with the same digit.

%C The sequence consists of groups of identical digits. The numbers representing each group, starting from the second group, form a cycle (5, 8, 1, 4, 7, 0, 3, 6, 9, 2).

%F a(n) = A358197(n) mod 10.

%F a(n) = A010879(A358197(n)).

%e a(3) = A358197(3) mod 10 = 15 mod 10 = 5,

%e a(4) = A358197(4) mod 10 = 98 mod 10 = 8,

%e a(9) = A358197(9) mod 10 = 221 mod 10 = 1.

%Y Cf. A010879, A358197.

%K nonn,base

%O 1,2

%A _Alexander M. Domashenko_, Nov 05 2022