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A177052
Ceiling(n/2)-abundant numbers.
2
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
OFFSET
1,1
COMMENTS
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.
LINKS
FORMULA
{n : Sum_{d|n, d<n} A004526(1+d) > A004526(1+n)}. [R. J. Mathar, Dec 11 2010]
PROG
(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
CROSSREFS
Sequence in context: A097216 A346695 A326133 * A023196 A376880 A204829
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Dec 09 2010
STATUS
approved