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Search: id:A126798
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| A126798 |
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A number n is included if, for at least one distinct prime p dividing n, p+1 divides n. |
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+0
1
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| 6, 12, 18, 24, 30, 36, 42, 48, 54, 56, 60, 66, 72, 78, 84, 90, 96, 102, 108, 112, 114, 120, 126, 132, 138, 144, 150, 156, 162, 168, 174, 180, 182, 186, 192, 198, 204, 210, 216, 222, 224, 228, 234, 240, 246, 252, 258, 264, 270, 276, 280, 282, 288, 294, 300, 306
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The sequence contains all the positive multiples of 6.
Numbers not == 0 (mod 6): 56, 112, 182, 224, 280, 364, 380, 392, 448, 560, 616, 728, 760, 784, 896, 910, 952, 992, ..., . - Robert G. Wilson v.
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EXAMPLE
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The distinct primes that divide 56 are 2 and 7. 56 is included in the sequence because (7+1)=8 divides 56.
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MAPLE
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with(numtheory): a:=proc(n) local A, fsn, j: fsn:=factorset(n): A:={}: for j from 1 to nops(fsn) do if type(n/(1+fsn[j]), integer)=true then A:=A union {j} else A:=A: fi: od: if nops(A)>0 then n else fi end: seq(a(n), n=2..370); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 28 2007
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MATHEMATICA
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fQ[n_] := Block[{fi = First /@ FactorInteger@n + 1}, MemberQ[IntegerQ /@ (n/fi), True]]; Select[ Range@ 300, fQ@# &] (* Robert G. Wilson v *)
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CROSSREFS
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Sequence in context: A102883 A044891 A121827 this_sequence A008458 A008588 A078596
Adjacent sequences: A126795 A126796 A126797 this_sequence A126799 A126800 A126801
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Mar 14 2007
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 28 2007
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