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 A280516 Amicable pairs where only deficient aliquot parts are considered. 1
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Subsequence of A063990. LINKS EXAMPLE 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. MAPLE 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); MATHEMATICA defQ[n_] := DivisorSigma[1, n] < 2n; s[n_] := DivisorSum[n, #&, #n && s[m]==n, AppendTo[seq, {n, m}]], {n, 1, 10^5}]; Flatten[seq] (* Amiram Eldar, Jan 26 2019 *) CROSSREFS Cf. A063990, A259180, A280515. Sequence in context: A320716 A269017 A328064 * A205994 A345540 A345792 Adjacent sequences:  A280513 A280514 A280515 * A280517 A280518 A280519 KEYWORD nonn,tabf AUTHOR Paolo P. Lava, Jan 04 2017 EXTENSIONS More terms from Amiram Eldar, Jan 26 2019 STATUS approved

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Last modified November 29 14:50 EST 2021. Contains 349416 sequences. (Running on oeis4.)