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A334973 Odd bi-unitary admirable numbers: the odd terms of A334972. 2

%I

%S 945,43065,46035,48195,80535,354585,403095,430815,437745,442365,

%T 458055,2305875,3525795,4404105,4891887,5388495,5803245,6126645,

%U 6220665,6375105,6537375,7853625,7981875,8109585,8731125,9071865,9338595,9784125,13241745,13351635,23760555

%N Odd bi-unitary admirable numbers: the odd terms of A334972.

%C Of the first 10^4 bi-unitary admirable numbers only 11 are odd.

%t fun[p_, e_] := If[OddQ[e], (p^(e + 1) - 1)/(p - 1), (p^(e + 1) - 1)/(p - 1) - p^(e/2)]; bsigma[1] = 1; bsigma[n_] := Times @@ (fun @@@ FactorInteger[n]); buDivQ[n_, 1] = True; buDivQ[n_, div_] := If[Mod[#2, #1] == 0, Last@Apply[Intersection, Map[Select[Divisors[#], Function[d, CoprimeQ[d, #/d]]] &, {#1, #2/#1}]] == 1, False] & @@ {div, n}; buAdmQ[n_] := (ab = bsigma[n] - 2 n) > 0 && EvenQ[ab] && ab/2 < n && Divisible[n, ab/2] && buDivQ[n, ab/2]; Select[Range[1, 5*10^5, 2], buAdmQ]

%Y The bi-unitary version of A109729.

%Y Intersection of A005408 and A334972.

%Y Subsequence of A293186.

%Y Cf. A329188, A334975.

%K nonn

%O 1,1

%A _Amiram Eldar_, May 18 2020

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Last modified September 19 03:31 EDT 2021. Contains 347550 sequences. (Running on oeis4.)