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A028373
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The straight sequence: numbers that have only the straight digits {1, 4, 7}.
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6
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1, 4, 7, 11, 14, 17, 41, 44, 47, 71, 74, 77, 111, 114, 117, 141, 144, 147, 171, 174, 177, 411, 414, 417, 441, 444, 447, 471, 474, 477, 711, 714, 717, 741, 744, 747, 771, 774, 777, 1111, 1114, 1117, 1141, 1144, 1147, 1171, 1174, 1177, 1411, 1414, 1417, 1441
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..52.
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MATHEMATICA
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f[n_] := Block[{id = IntegerDigits[n], straight = {1, 4, 7}}, If[ Union[ Join[id, straight]] == straight, True, False]]; Select[ Range[0, 1446], f[ # ] & ]
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PROG
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(PARI) is(n)=my(t); while(n, t=n%10; if(t!=1&&t!=4&&t!=7, return(0)); n\=10); !!t \\ Charles R Greathouse IV, Sep 25 2012
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CROSSREFS
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Cf. A028374, the curved sequence.
Sequence in context: A195171 A184623 A184581 * A190769 A083051 A198269
Adjacent sequences: A028370 A028371 A028372 * A028374 A028375 A028376
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KEYWORD
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easy,nonn,base
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AUTHOR
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Greg Heil (gheil(AT)scn.org)
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STATUS
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approved
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