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A316096
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Numbers n such that A(n+1) = A(n) + 4, where A() = A005101() are the abundant numbers.
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2
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3, 6, 11, 13, 17, 18, 21, 24, 25, 32, 35, 40, 43, 46, 47, 50, 53, 60, 63, 64, 69, 72, 75, 78, 85, 88, 91, 94, 95, 100, 105, 106, 109, 112, 115, 117, 121, 124, 127, 130, 132, 136, 139, 140, 147, 148, 151, 154, 157, 159, 165, 168, 171, 176, 177, 180, 181, 184
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OFFSET
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1,1
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LINKS
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FORMULA
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Sequence is { n | A125115(n) = 4 }.
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MAPLE
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with(numtheory): A:=select(n->sigma(n)>2*n, [$1..1000]): a:=select(j->A[j+1]=A[j]+4, [$1..nops(A)-1]);
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MATHEMATICA
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Position[Map[{#1, #2 - 4} & @@ # &, Partition[Select[Range[10^3], DivisorSigma[1, #] > 2 # &], 2, 1]], _?(SameQ @@ # &)][[All, 1]] (* Michael De Vlieger, Jun 29 2018 *)
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PROG
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(GAP) A:=Filtered([1..1000], n->Sigma(n)>2*n);; a:=Filtered([1..Length(A)-1], i->A[i+1]=A[i]+4);
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CROSSREFS
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A316098 is the main sequence for this entry.
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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