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A082729
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Least positive number that can be written using all divisors of n and the operations add and subtract.
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2
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1, 1, 2, 1, 4, 2, 6, 1, 5, 2, 10, 2, 12, 4, 6, 1, 16, 1, 18, 2, 10, 8, 22, 2, 19, 10, 14, 2, 28, 2, 30, 1, 18, 14, 22, 1, 36, 16, 22, 2, 40, 2, 42, 4, 12, 20, 46, 2, 41, 7, 30, 6, 52, 2, 38, 2, 34, 26, 58, 2, 60, 28, 22, 1, 46, 2, 66, 10, 42, 2, 70, 1, 72, 34, 26, 12, 58, 2, 78, 2, 41, 38, 82
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| a(n) < A000203(n); a(n)=A000010(n)=n-1 iff n is prime or n=6;
a(2^n)=1, a(A000079(n))=1.
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EXAMPLE
| Divisors of n=18: {1,2,3,6,9,18} -> a(18)=-1+2-3-6-9+18=1.
divisors of n=15: {1,3,5,15} -> a(15)=-1-3-5+15=6, as
-1-3-5-15<1, 1-3-5-15<1, -1+3-5-15<1, 1+3-5-15<1, -1-3+5-15<1, 1-3+5-15<1,
-1+3+5-15<1, 1+3+5-15<1, 1-3-5+15>6, -1+3-5+15>6, 1+3-5+15>6, -1-3+5+15>6,
1-3+5+15>6, -1+3+5+15>6 and 1+3+5+15>6.
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CROSSREFS
| Cf. A081806, A000005.
Sequence in context: A187202 A125131 A003958 * A175542 A076686 A114810
Adjacent sequences: A082726 A082727 A082728 * A082730 A082731 A082732
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KEYWORD
| nonn
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Apr 13 2003
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