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

945, 43065, 46035, 48195, 80535, 354585, 403095, 430815, 437745, 442365, 458055, 2305875, 3525795, 4404105, 4891887, 5388495, 5803245, 6126645, 6220665, 6375105, 6537375, 7853625, 7981875, 8109585, 8731125, 9071865, 9338595, 9784125, 13241745, 13351635, 23760555

Offset

1,1

Comments

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

Links

Table of n, a(n) for n=1..31.

Mathematica

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]

Crossrefs

The bi-unitary version of A109729.

Intersection of A005408 and A334972.

Subsequence of A293186.

Cf. A329188, A334975.

Sequence in context: A290034 A335055 A133818 * A334975 A289953 A112491

Adjacent sequences: A334970 A334971 A334972 * A334974 A334975 A334976

Keyword

nonn

Author

Amiram Eldar, May 18 2020

Status

approved