A358257 The least significant digit of k such that 2^k, 5^k, 8^k start with the same digit.

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, 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, 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

Offset

1,2

Comments

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).

Links

Table of n, a(n) for n=1..105.

Formula

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

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

Example

a(3) = A358197(3) mod 10 = 15 mod 10 = 5,
a(4) = A358197(4) mod 10 = 98 mod 10 = 8,
a(9) = A358197(9) mod 10 = 221 mod 10 = 1.

Crossrefs

Cf. A010879, A358197.

Sequence in context: A245189 A217169 A141538 * A003861 A107623 A218333

Adjacent sequences: A358254 A358255 A358256 * A358258 A358259 A358260

Keyword

nonn,base

Author

Alexander M. Domashenko, Nov 05 2022

Status

approved