|
Search: id:A088829
|
|
|
| A088829 |
|
Even numbers with even abundance. |
|
+0
3
|
|
| 6, 10, 12, 14, 20, 22, 24, 26, 28, 30, 34, 38, 40, 42, 44, 46, 48, 52, 54, 56, 58, 60, 62, 66, 68, 70, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 130, 132, 134, 136, 138, 140, 142, 146, 148, 150, 152
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Odd numbers with odd abundance are in A016754. Odd numbers with even abundance are in A088828. Even numbers with odd abundance are in A088827.
|
|
EXAMPLE
|
Even perfect numbers are here.
n=10: sigma[10]=18, abundance=18-20=-2<0;
n=12: sigma[12]=28, abundance=28-24=+4>0.
sigma[n] is also even number; sign of abundance:<=>0.
|
|
MATHEMATICA
|
Do[s=DivisorSigma[1, n]-2*n; If[ !OddQ[s]&&!OddQ[n], Print[{n, s}]], {n, 1, 1000}]
|
|
CROSSREFS
|
Cf. A016754, A088827-A088828, A088830.
Sequence in context: A114989 A129493 A036350 this_sequence A036348 A100368 A128691
Adjacent sequences: A088826 A088827 A088828 this_sequence A088830 A088831 A088832
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Labos E. (labos(AT)ana.sote.hu), Oct 28 2003
|
|
|
Search completed in 0.002 seconds
|
