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A177084 Ceiling(n/3)-perfect numbers. 2
2, 3, 4, 10, 14, 50, 52, 130, 184, 315, 688, 988, 2528, 6490, 35456, 396916, 537088, 538112, 801376, 1297312, 8452096, 8456192, 35221184, 53996590, 134520832, 222469702 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
For definition, see comment of A175522.
LINKS
FORMULA
{n: Sum_{d|n, d<n} A002264(2+d) = A002264(2+n)}. - R. J. Mathar, Dec 11 2010
MATHEMATICA
aQ[n_] := DivisorSum[n, Ceiling[#/3] &, # < n &] == Ceiling[n/3]; Select[Range[10^6], aQ] (* Amiram Eldar, Jul 20 2019 *)
PROG
(Sage) is_A177084 = lambda n: sum(ceil(d/3) for d in divisors(n)) == 2*ceil(n/3) # D. S. McNeil, Dec 10 2010
CROSSREFS
Sequence in context: A131120 A115195 A095384 * A362664 A115899 A183527
KEYWORD
nonn,more
AUTHOR
Vladimir Shevelev, Dec 09 2010
EXTENSIONS
a(21)-a(26) from Amiram Eldar, Jul 20 2019
STATUS
approved

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Last modified July 18 21:02 EDT 2024. Contains 374388 sequences. (Running on oeis4.)