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 A181596 Abundance of A181595(n). 7
 4, 3, 2, 12, 10, 8, 4, 2, 7, 56, 78, 8, 2, 2, 32, 16, 4, 2, 532, 152, 136, 8, 68, 31, 992, 128, 8, 64, 32, 16, 4, 8, 128, 32, 8, 2, 43648, 2528, 32, 4, 2, 32, 2272, 32, 32, 127, 16256, 32, 32, 4, 536, 8, 32, 8, 52, 16, 32, 41044, 64, 512, 128, 64, 16, 4, 2, 8 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) is a proper divisor of A181595(n). LINKS Michel Marcus, Table of n, a(n) for n = 1..200 Paul Pollack and Vladimir Shevelev, On perfect and near-perfect numbers, J. Number Theory 132 (2012), pp. 3037-3046. arXiv:1011.6160 FORMULA a(n) = A033880(A181595(n)). EXAMPLE Since A181595(1)=12, a(1)=sigma(12)-2*12=28-24=4. MATHEMATICA Reap[For[n = 12, n <= 2 10^7, n++, abn = DivisorSigma[1, n] - 2n; If[1 < abn < n && Divisible[n, abn], Print[{n, abn}]; Sow[abn]]]][[2, 1]] (* Jean-François Alcover, Oct 28 2018 *) CROSSREFS Cf. A181595, A000396, A005101, A153501, A005820. Sequence in context: A333780 A033882 A062111 * A182142 A033881 A099406 Adjacent sequences: A181593 A181594 A181595 * A181597 A181598 A181599 KEYWORD nonn AUTHOR Vladimir Shevelev, Nov 01 2010 EXTENSIONS a(10)-a(11) corrected by Vladimir Shevelev, Nov 03 2010 Entries checked, definition shortened by R. J. Mathar, Nov 17 2010 More terms from Michel Marcus, Feb 06 2016 STATUS approved

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Last modified March 2 12:02 EST 2024. Contains 370467 sequences. (Running on oeis4.)