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 A306872 Lesser of augmented unitary amicable pair. 2
 6224890, 37542190, 56523810, 101304490, 135657795, 233990890, 5304907426, 8473747030, 8483430670, 9220653310, 11033448910, 12139959910, 13108452735, 13849730895, 16697472870, 19644687195, 20321234206, 23076788295, 40575765615, 55636542346, 89094853155, 101786530846 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A pair m < n is an augmented unitary amicable pair if usigma(m) = usigma(n) = m + n - 1, where usigma(n) is the sum of unitary divisors of n (A034460). The larger members are in A306873. LINKS Amiram Eldar, Table of n, a(n) for n = 1..27 (terms below 10^12, from David Moews's site). David Moews, Perfect, amicable and sociable numbers J. O. M. Pedersen, Tables of Aliquot Cycles EXAMPLE 6224890 is in the sequence since it is the lesser of the amicable pair (6224890, 7336455): usigma(6224890) = usigma(7336455) = 13561344 = 6224890 + 7336455 - 1. MATHEMATICA us[n_] := Times @@ (1 + Power @@@ FactorInteger[n]) - n;  s={}; Do[m = us[n] + 1; If[m > n && us[m] == n - 1, AppendTo[s, n]], {n, 1, 10^9}]; s CROSSREFS Cf. A002952, A007992, A034460, A126174, A306873. Sequence in context: A254360 A224640 A185887 * A186838 A204654 A138941 Adjacent sequences:  A306869 A306870 A306871 * A306873 A306874 A306875 KEYWORD nonn AUTHOR Amiram Eldar, Mar 14 2019 STATUS approved

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Last modified April 8 21:44 EDT 2020. Contains 333329 sequences. (Running on oeis4.)