login
A244894
Composite numbers n with the property that the symmetric representation of sigma(n) has two parts.
5
10, 14, 22, 26, 34, 38, 44, 46, 52, 58, 62, 68, 74, 76, 78, 82, 86, 92, 94, 102, 106, 114, 116, 118, 122, 124, 134, 136, 138, 142, 146, 148, 152, 158, 164, 166, 172, 174, 178, 184, 186, 188, 194, 202, 206, 212, 214, 218, 222, 226, 232, 236, 244, 246, 248, 254, 258, 262, 268, 274, 278, 282, 284, 292, 296, 298, 302, 314, 316, 318, 326, 328, 332, 334, 344, 346, 348, 354, 356, 358
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
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].
.
. _ _ _ _ _ _ _ _ _ _ _ _ _ _
. | _ _ _ _ _ _ _ _ _ _ _ _ _|
. | |
. | |
. | | _ _ _ _ _ _ _ _ _ _ _ _
. 21 _ _| | | _ _ _ _ _ _ _ _ _ _ _|
. |_ _ _| | |
. _ _| | |
. _| 18 _ _| |
. | |_ _ _|
. 21 _ _| _|
. | | _|
. _ _ _ _ _| | 18 _ _| _ _ _ _ _ _ _ _
. | _ _ _ _ _| | | | _ _ _ _ _ _ _|
. | | _ _ _ _| | | |
. | | | _ _ _ _| 12 _| |
. | | | | |_ _| _ _ _ _ _ _
. | | | | 12 _ _| | _ _ _ _ _|
. | | | | _ _ _| | 9 _| |
. | | | | | _ _ _| 9 _|_ _|
. | | | | | | _ _| |
. | | | | | | | _ _|
. | | | | | | | |
. | | | | | | | |
. | | | | | | | |
. | | | | | | | |
. |_| |_| |_| |_|
.
n: 26 22 14 10
.
Sigma(10) = 9 + 9 = 18.
Sigma(14) = 12 + 12 = 24.
Sigma(22) = 18 + 18 = 36.
Sigma(26) = 21 + 21 = 42.
.
CROSSREFS
Sequence in context: A253569 A138511 A319802 * A167611 A151740 A136802
KEYWORD
nonn
AUTHOR
Omar E. Pol, Jul 07 2014
EXTENSIONS
Extended by R. J. Mathar, Oct 04 2018
STATUS
approved