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A068090
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Numbers n which divide the right concatenation of the first n even numbers.
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0
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1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 14, 15, 18, 20, 24, 25, 30, 35, 36, 39, 40, 45, 50, 60, 72, 75, 80, 90, 100, 120, 125, 144, 150, 180, 200, 204, 225, 240, 250, 300, 360, 375, 400, 450, 500, 507, 540, 585, 600, 624, 625, 675, 702, 720, 750, 780, 800, 804, 864, 900
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OFFSET
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1,2
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LINKS
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EXAMPLE
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The right concatenation of the first six even numbers is 24681012 and 6 divides this number. So 6 is a member of the sequence.
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MAPLE
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a := proc(n): if n=1 then RETURN(2) fi: 2*n+a(n-1)*10^(ceil(log[10](2*n+.01))) end: for n from 1 to 1000 do if a(n) mod n = 0 then printf(`%d, `, n) fi; od:
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MATHEMATICA
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concat[n_]:=FromDigits[Flatten[IntegerDigits/@Range[2, 2n, 2]]]; Select[ Range[700], Divisible[concat[#], #]&] (* Harvey P. Dale, Nov 02 2011 *)
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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