A111395 First digit of powers of 5.

1, 5, 2, 1, 6, 3, 1, 7, 3, 1, 9, 4, 2, 1, 6, 3, 1, 7, 3, 1, 9, 4, 2, 1, 5, 2, 1, 7, 3, 1, 9, 4, 2, 1, 5, 2, 1, 7, 3, 1, 9, 4, 2, 1, 5, 2, 1, 7, 3, 1, 8, 4, 2, 1, 5, 2, 1, 6, 3, 1, 8, 4, 2, 1, 5, 2, 1, 6, 3, 1, 8, 4, 2, 1, 5, 2, 1, 6, 3, 1, 8, 4, 2, 1, 5, 2, 1, 6

Offset: 0

Author

Almerio A. Castro (almerio.castro(AT)gmail.com), Nov 11 2005

Keywords

• easy
• nonn
• base

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A008952, A060956.

Cf. A000030, A000351, A008566.

Programs

Mathematica

First[IntegerDigits[#]]&/@(5^Range[0,100]) (* Harvey P. Dale, Jan 13 2015 *)

PARI

a(n) = digits(5^n)[1]; \\ Michel Marcus, Jan 07 2014

Formula

a(n) = A000030(A000351(n)). - Seiichi Manyama, Jul 15 2023

Extensions

a(0)=1 prepended, and more terms from Michel Marcus, Jan 07 2014