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A214584
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Integers whose decimal representation has only digits in {4,5,7}.
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2
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4, 5, 7, 44, 45, 47, 54, 55, 57, 74, 75, 77, 444, 445, 447, 454, 455, 457, 474, 475, 477, 544, 545, 547, 554, 555, 557, 574, 575, 577, 744, 745, 747, 754, 755, 757, 774, 775, 777, 4444, 4445, 4447, 4454, 4455, 4457, 4474, 4475, 4477, 4544, 4545, 4547, 4554, 4555, 4557, 4574, 4575, 4577, 4744
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listen;
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OFFSET
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1,1
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COMMENTS
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These could be called crooked numbers. Integers all of whose numerals are written (san serif) with at least one right or acute angle. The subsequence of crooked primes begins: 5, 7, 47, 457, 547, 557, 577, 757.
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LINKS
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CROSSREFS
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Cf. A072960 (numbers using only the curved digits 0, 3, 6, 8 and 9).
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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