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A277548
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Numbers k such that k/5^m == 4 (mod 5), where 5^m is the greatest power of 5 that divides k.
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5
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4, 9, 14, 19, 20, 24, 29, 34, 39, 44, 45, 49, 54, 59, 64, 69, 70, 74, 79, 84, 89, 94, 95, 99, 100, 104, 109, 114, 119, 120, 124, 129, 134, 139, 144, 145, 149, 154, 159, 164, 169, 170, 174, 179, 184, 189, 194, 195, 199, 204, 209, 214, 219, 220, 224, 225, 229
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OFFSET
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1,1
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COMMENTS
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Positions of 4 in A277543. Numbers that have 4 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. All these sequences have the same density of 1/4.
Is there some n with a 3 or a 4 in base 5 such that a(n) = 4n + 1? - David A. Corneth, Oct 23 2016
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LINKS
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Clark Kimberling, Table of n, a(n) for n = 1..10000
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FORMULA
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Conjecture: a(n) = 4*n if and only if n is in A033042. - David A. Corneth, Oct 23 2016
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MATHEMATICA
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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 *)
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PROG
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(PARI) isok(n) = n/5^valuation(n, 5) % 5 == 4; \\ Michel Marcus, Oct 21 2016
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CROSSREFS
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Cf. A033042, A277543, A277550, A277551, A277555.
Sequence in context: A043365 A023738 A070799 * A031474 A045203 A313082
Adjacent sequences: A277545 A277546 A277547 * A277549 A277550 A277551
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KEYWORD
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nonn,easy
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AUTHOR
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Clark Kimberling, Oct 20 2016
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STATUS
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approved
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