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A263808
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Numbers k such that the iterated subtraction of the decimal digits eventually reaches -k.
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2
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1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 18, 20, 21, 22, 24, 27, 30, 33, 36, 40, 42, 44, 45, 48, 50, 51, 54, 55, 60, 63, 66, 70, 72, 77, 80, 81, 84, 88, 89, 90, 98, 99, 100, 101, 102, 105, 108, 110, 111, 112, 113, 114, 116, 117, 120, 123, 124, 126, 128
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OFFSET
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1,2
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COMMENTS
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LINKS
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EXAMPLE
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a(14)=18: 18-1-8-1-8-1-8-1-8 = -18. - Bob Selcoe, Oct 27 2015
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MATHEMATICA
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eQ[n_] := Block[{d = IntegerDigits@ n}, MemberQ[Accumulate@ d ~Prepend~ 0, Mod[2*n, Total@ d]]]; Select[Range@ 128, eQ] (* Giovanni Resta, Oct 27 2015 *)
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PROG
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(Haskell)
a263808 n = a263808_list !! (n-1)
a263808_list = filter essicran [1..] where
essicran x = last (takeWhile (>= -x) es) == -x where
es = scanl (-) x (cycle $ map (read . return) $ show x)
(PARI) is(n)=my(d=digits(n), t, S=vector(#d-1, i, t+=d[i])); t=2*n%vecsum(d); t==0 || setsearch(S, d) \\ Charles R Greathouse IV, Oct 28 2015
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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