A244894 Composite numbers n with the property that the symmetric representation of sigma(n) has two parts.

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

Author

Omar E. Pol, Jul 07 2014

Keywords

• nonn

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.

Examples

			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.
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Links

• R. J. Mathar, Table of n, a(n) for n = 1..999

Crossrefs

Cf. A237271 (number of parts), A237270, A237593, A238443, A238524, A239660, A239929, A239932, A239934, A245092, A262626, A280107 (4 parts).

Extensions

Extended by R. J. Mathar, Oct 04 2018