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A088723
Numbers k with at least one divisor d>1 such that d+1 also divides k.
11
6, 12, 18, 20, 24, 30, 36, 40, 42, 48, 54, 56, 60, 66, 72, 78, 80, 84, 90, 96, 100, 102, 108, 110, 112, 114, 120, 126, 132, 138, 140, 144, 150, 156, 160, 162, 168, 174, 180, 182, 186, 192, 198, 200, 204, 210, 216, 220, 222, 224, 228, 234, 240, 246, 252, 258, 260
OFFSET
1,1
COMMENTS
A088722(a(n))>0; complement of A088725.
Complement of A132895 relative to A005843, the even numbers. - Chandler
LINKS
MATHEMATICA
Select[Range[300], MemberQ[Differences[Select[Divisors[#], #>1&]], 1]&] (* Harvey P. Dale, Apr 03 2011 *)
PROG
(Haskell)
a088723 n = a088723_list !! (n-1)
a088723_list = filter f [2..] where
f x = 1 `elem` (zipWith (-) (tail divs) divs)
where divs = tail $ a027750_row x
-- Reinhard Zumkeller, Dec 16 2013
CROSSREFS
Cf. A027750, A008588 (subsequence).
Sequence in context: A324652 A205525 A094519 * A228870 A291022 A348719
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Oct 12 2003
EXTENSIONS
Extended by Ray Chandler, May 29 2008
STATUS
approved