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Odd unitary admirable numbers: the odd terms of A328328.
4

%I #15 May 14 2020 11:06:39

%S 80535,354585,403095,430815,437745,442365,5388495,6126645,9338595,

%T 36340395,130689195,747242265,1335049485,2224695165,4085490255,

%U 9665740455,10394173335,11534750535,13837748925,33378237165,73088757105,94849396005,109544822205,216654032595

%N Odd unitary admirable numbers: the odd terms of A328328.

%C Of the first 10^4 unitary admirable numbers only 6 are odd.

%C a(21) > 6*10^10.

%H Giovanni Resta, <a href="/A329188/b329188.txt">Table of n, a(n) for n = 1..43</a> (terms < 10^13)

%t usigma[1] = 1; usigma[n_] := Times @@ (1 + Power @@@ FactorInteger[n]); uadmQ[n_] := (ab = usigma[n] - 2 n) > 0 && EvenQ[ab] && ab/2 < n && Divisible[n, ab/2] && CoprimeQ[2*n/ab, ab/2]; s = {}; Do[If[uadmQ[n], AppendTo[s, n]], {n, 1, 10^6, 2}]; s

%Y The unitary version of A109729.

%Y Intersection of A005408 and A328328.

%Y Subsequence of A129485.

%K nonn

%O 1,1

%A _Amiram Eldar_, Nov 07 2019

%E Data corrected by _Amiram Eldar_, May 12 2020

%E Terms a(21) and beyond from _Giovanni Resta_, May 12 2020