A277550 Numbers k such that k/5^m == 1 (mod 5), where 5^m is the greatest power of 5 that divides k.

1, 5, 6, 11, 16, 21, 25, 26, 30, 31, 36, 41, 46, 51, 55, 56, 61, 66, 71, 76, 80, 81, 86, 91, 96, 101, 105, 106, 111, 116, 121, 125, 126, 130, 131, 136, 141, 146, 150, 151, 155, 156, 161, 166, 171, 176, 180, 181, 186, 191, 196, 201, 205, 206, 211, 216, 221

Offset

1,2

Comments

Positions of 1 in A277543. Numbers that have 1 as their rightmost nonzero digit when written in base 5.

This is one sequence in a 4-way splitting of the positive integers; the other three are indicated in the Mathematica program.

Links

Clark Kimberling, Table of n, a(n) for n = 1..10000

Mathematica

z = 200; a[b_] := Table[Mod[n/b^IntegerExponent[n, b], b], {n, 1, z}]
p[b_, d_] := Flatten[Position[a[b], d]]
p[5, 1] (* A277550 *)
p[5, 2] (* A277551 *)
p[5, 3] (* A277555 *)
p[5, 4] (* A277548 *)

Prog

(PARI) isok(n) = n/5^valuation(n, 5) % 5 == 1; \\ Michel Marcus, Oct 21 2016

Crossrefs

Cf. A277543, A277551, A277555, A277548.

Sequence in context: A083450 A136974 A101187 * A070373 A231000 A274283

Adjacent sequences: A277547 A277548 A277549 * A277551 A277552 A277553

Keyword

nonn,easy

Author

Clark Kimberling, Oct 20 2016

Status

approved