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 A144672 Numbers x,y,z such that UnitarySigma(x) = UnitarySigma(y) = UnitarySigma(z) = 3*(x*y*z)^(1/2)/(- x^(1/2) + 8*y^(1/2) - 5*z^(1/2)), z<=y<=x; sequence gives x. 4
 2, 20, 24, 360, 816, 1056, 12240, 15840, 29120, 181632, 337977, 2724480, 93358848, 1400382720 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(11) is the smallest term for x!=y, y!=z, x!=z. If x=y=z then we get multiply unitary perfect numbers such that UnitarySigma(x)=3x/2. LINKS Table of n, a(n) for n=1..14. EXAMPLE Factorization of a(11) : 17*3^2*47^2. CROSSREFS Cf. A034448, A144673, A144674 (these entries all differ at a(11)). Sequence in context: A196748 A144674 A144673 * A145681 A108061 A154546 Adjacent sequences: A144669 A144670 A144671 * A144673 A144674 A144675 KEYWORD nonn,more AUTHOR Yasutoshi Kohmoto, Feb 02 2009 STATUS approved

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Last modified June 21 06:22 EDT 2024. Contains 373540 sequences. (Running on oeis4.)