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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

Table of n, a(n) for n=1..26.

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

Cf. A000396, A002264, A175522, A175807, A175853, A177050.

Sequence in context: A131120 A115195 A095384 * A115899 A183527 A085934

Adjacent sequences:  A177081 A177082 A177083 * A177085 A177086 A177087

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 October 3 15:08 EDT 2022. Contains 357237 sequences. (Running on oeis4.)