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Search: id:A129486
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| A129486 |
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Odd unitary abundant numbers that are not odd, squarefree, ordinary abundant numbers. |
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+0
2
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| 195195, 333795, 416955, 1786785, 1996995, 2417415, 2807805, 3138135, 3318315, 3708705, 3798795, 4103715, 4339335, 4489485, 4789785, 4967655, 5120115, 5420415, 5552085, 5660655, 5731635, 6051045, 6111105, 6263565, 6342105
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The first 50 members of A129485 and A112643 are the same. However, the sequences differ thereafter and this sequence contains those integers that are included in A129485 but are not included in A112643.
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LINKS
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Eric Weisstein, Unitary Divisor.
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FORMULA
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The complement of A129485 and A112643.
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EXAMPLE
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The third integer which is an odd unitary abundant number but is not an ordinary, squarefree abundant number is 416955. Hence a(3)=416955.
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MATHEMATICA
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UnitaryDivisors[ n_Integer?Positive ] := Select[ Divisors[ n ], GCD[ #, n/# ] == 1 & ]; sstar[ n_ ] := Plus @@ UnitaryDivisors[ n ] - n; UnitaryAbundantNumberQ[ k_ ] := If[ sstar[ k ] > k, True, False ]; data1 = Select[ Range[ 1, 10^7, 2 ], UnitaryAbundantNumberQ[ # ] & ]; data2 = Select[ Range[ 1, 10^7, 2 ], DivisorSigma[ 1, # ] - 2 # > 0 && ! MoebiusMu[ # ] == 0 & ]; Complement[ data1, data2 ]
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CROSSREFS
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Cf. A034683, A129485, A034460, A034448, A129487, A002827, A129468, A112643.
Sequence in context: A131907 A013901 A069305 this_sequence A074388 A008408 A001942
Adjacent sequences: A129483 A129484 A129485 this_sequence A129487 A129488 A129489
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KEYWORD
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easy,nonn
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AUTHOR
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Ant King (mathstutoring(AT)ntlworld.com), Apr 17 2007
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