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 A088829 Even numbers with even abundance. 6
 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; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Odd numbers with odd abundance are in A016754. Odd numbers with even abundance are in A088828. Even numbers with odd abundance are in A088827. LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 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: A129493 A036350 A295076 * A036348 A100368 A128691 Adjacent sequences:  A088826 A088827 A088828 * A088830 A088831 A088832 KEYWORD nonn AUTHOR Labos Elemer, Oct 28 2003 STATUS approved

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Last modified January 19 12:10 EST 2022. Contains 350465 sequences. (Running on oeis4.)