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The structure of digits represents a convex function or a convex object. In the graphic representation the points are connected by imaginary line segments (or line curves) from left to right.
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The structure of digits represent represents a convex function or a convex object. In the graphic representation the points are connected by imaginary line segments (or line curves) from left to right.
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. . . . . 5
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. . . . 3 .
. . 2 2 . .
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convexQ[n_] := With[{dd = IntegerDigits[n]}, AllTrue[SequencePosition[dd, {_, _, _}][[All, 1]], dd[[#]] + dd[[#+2]] > 2 dd[[#+1]]&]];
Select[Range[100, 300], convexQ] (* Jean-François Alcover, Nov 01 2018 *)
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