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A280516
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Amicable pairs where only deficient aliquot parts are considered.
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1
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1184, 1210, 6232, 6368, 10744, 10856, 66928, 66992, 522405, 525915, 643336, 652664, 5459176, 5495264, 7677248, 7684672, 16137628, 16150628, 25596544, 25640096, 26090325, 26138475, 28118032, 28128368, 34364912, 34380688, 133178325, 133471275, 164733752, 166212808
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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Deficient aliquot parts of 1184 are 1,2,4,8,16,32,37,74,148,296,592 and their sum is 1210.
Deficient aliquot parts of 1210 are 1,2,5,10,11,22,55,110,121,242,605 and their sum is 1184.
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MAPLE
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with(numtheory): P:=proc(q) local a, b, c, d, k, n; for n from 1 to q do
a:=sort([op(divisors(n))]); b:=0; for k from 1 to nops(a)-1 do if 2*a[k]>sigma(a[k]) then b:=b+a[k]; fi; od;
c:=sort([op(divisors(b))]); d:=0; for k from 1 to nops(c)-1 do if 2*c[k]>igma(c[k]) then d:=d+c[k]; fi; od; if d=n and d<>b then print(n); fi; od; end: P(10^6);
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MATHEMATICA
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defQ[n_] := DivisorSigma[1, n] < 2n; s[n_] := DivisorSum[n, #&, #<n && defQ[#]&]; seq={}; Do[m=s[n]; If[m>n && s[m]==n, AppendTo[seq, {n, m}]], {n, 1, 10^5}]; Flatten[seq] (* Amiram Eldar, Jan 26 2019 *)
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CROSSREFS
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KEYWORD
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nonn,tabf
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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