OFFSET
1,1
COMMENTS
Even numbers in A239929.
By definition the two parts of the symmetric representation of sigma(n) are sigma(n)/2 and sigma(n)/2.
LINKS
R. J. Mathar, Table of n, a(n) for n = 1..999
EXAMPLE
Illustration of the symmetric representation of sigma(n) in the second quadrant for the first four elements of this sequence: [10, 14, 22, 26].
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. _ _ _ _ _ _ _ _ _ _ _ _ _ _
. | _ _ _ _ _ _ _ _ _ _ _ _ _|
. | |
. | |
. | | _ _ _ _ _ _ _ _ _ _ _ _
. 21 _ _| | | _ _ _ _ _ _ _ _ _ _ _|
. |_ _ _| | |
. _ _| | |
. _| 18 _ _| |
. | |_ _ _|
. 21 _ _| _|
. | | _|
. _ _ _ _ _| | 18 _ _| _ _ _ _ _ _ _ _
. | _ _ _ _ _| | | | _ _ _ _ _ _ _|
. | | _ _ _ _| | | |
. | | | _ _ _ _| 12 _| |
. | | | | |_ _| _ _ _ _ _ _
. | | | | 12 _ _| | _ _ _ _ _|
. | | | | _ _ _| | 9 _| |
. | | | | | _ _ _| 9 _|_ _|
. | | | | | | _ _| |
. | | | | | | | _ _|
. | | | | | | | |
. | | | | | | | |
. | | | | | | | |
. | | | | | | | |
. |_| |_| |_| |_|
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n: 26 22 14 10
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Sigma(10) = 9 + 9 = 18.
Sigma(14) = 12 + 12 = 24.
Sigma(22) = 18 + 18 = 36.
Sigma(26) = 21 + 21 = 42.
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CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, Jul 07 2014
EXTENSIONS
Extended by R. J. Mathar, Oct 04 2018
STATUS
approved