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Search: id:A088912
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| A088912 |
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Smallest m such that sigma(m)=(n+1/2)*m. |
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+0
1
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OFFSET
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1,1
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COMMENT
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The next term of this sequence is greater than 5*10^9. 2 is the only number m such that sigma(m)=1.5*m.
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FORMULA
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a[n_] := (For[m=1, DivisorSigma[1, m]!=(n+1/2)m, m++ ];m)
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EXAMPLE
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a(2)=24 because 1+2+3+4+6+8+12+24=2.5*24 and 24 is the earliest m such that sigma(m)=2.5*m.
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MATHEMATICA
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a[n_] := (For[m=1, DivisorSigma[1, m]!=(n+1/2)m, m++ ]; m); Do[Print[a[n]], {n, 4}]
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CROSSREFS
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Cf. A007539, A055153, A000396, A005820, A027687.
Adjacent sequences: A088909 A088910 A088911 this_sequence A088913 A088914 A088915
Sequence in context: A111430 A059332 A000794 this_sequence A055462 A088600 A066120
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KEYWORD
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hard,more,nonn
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AUTHOR
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Farideh Firoozbakht (f.firoozbakht(AT)sci.ui.ac.ir), Nov 29 2003
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