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A277550
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Numbers k such that k/5^m == 1 (mod 5), where 5^m is the greatest power of 5 that divides k.
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5
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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
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OFFSET
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1,2
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COMMENTS
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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.
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LINKS
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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]]
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PROG
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(PARI) isok(n) = n/5^valuation(n, 5) % 5 == 1; \\ Michel Marcus, Oct 21 2016
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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