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A177052
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Ceiling(n/2)-abundant numbers.
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2
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6, 12, 18, 20, 24, 28, 30, 36, 40, 42, 48, 54, 56, 60, 66, 70, 72, 78, 80, 84, 88, 90, 96, 100, 102, 104, 108, 112, 114, 120, 126, 132, 138, 140, 144, 150, 156, 160, 162, 168, 174, 176, 180, 186, 192, 196, 198, 200, 204, 208, 210, 216, 220, 222, 224, 228
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OFFSET
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1,1
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COMMENTS
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For definition, see A175522.
All positive numbers == 0 (mod 6) are in the sequence (basically A008588). In addition, note that all odd primes are ceiling(n/2)-deficient numbers. The first odd term of the sequence is 315.
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LINKS
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Amiram Eldar, Table of n, a(n) for n = 1..10000
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FORMULA
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{n : Sum_{d|n, d<n} A004526(1+d) > A004526(1+n)}. [R. J. Mathar, Dec 11 2010]
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PROG
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(Sage) is_A177052 = lambda n: sum(ceil(d/2) for d in divisors(n)) > 2*ceil(n/2) # D. S. McNeil, Dec 10 2010
(PARI) isok(n) = sumdiv(n, d, (d<n)*ceil(d/2)) > ceil(n/2); \\ Michel Marcus, Feb 08 2016
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CROSSREFS
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Cf. A177050 (perfect version), A005100, A005101, A175524, A175526, A175811, A175821, A175853.
Sequence in context: A097216 A346695 A326133 * A023196 A204829 A005835
Adjacent sequences: A177049 A177050 A177051 * A177053 A177054 A177055
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KEYWORD
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nonn
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AUTHOR
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Vladimir Shevelev, Dec 09 2010
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STATUS
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approved
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