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 A087381 Let Compri(n) be the number obtained by replacing each prime digit (2,3,5,7) of n with a '1' and a composite digit( 0,4,6,8,9) with a '0'. A 1 remains the same. a(n) = Compri(n). 1
 1, 1, 1, 0, 1, 0, 1, 0, 0, 10, 11, 11, 11, 10, 11, 10, 11, 10, 10, 10, 11, 11, 11, 10, 11, 10, 11, 10, 10, 10, 11, 11, 11, 10, 11, 10, 11, 10, 10, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 10, 11, 11, 11, 10, 11, 10, 11, 10, 10, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 10, 11, 11, 11, 10, 11, 10, 11, 10, 10, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,10 COMMENTS For all numbers using only composite digits (0,4,6,8,9) a(n) = 0. For a 'k' digit number using 1 and/or only prime digits a(n) = (10^k-1)/9. LINKS Table of n, a(n) for n=1..80. EXAMPLE a(4206) = 100 a(10235479) = 10111010 MATHEMATICA Join[{1}, Table[FromDigits[IntegerDigits[n]/.{2->1, 3->1, 4->0, 5->1, 6->0, 7->1, 8->0, 9->0}], {n, 2, 100}]] (* Harvey P. Dale, Jul 12 2020 *) CROSSREFS Cf. A087380. Sequence in context: A077812 A004288 A065016 * A136400 A334027 A121266 Adjacent sequences: A087378 A087379 A087380 * A087382 A087383 A087384 KEYWORD base,nonn AUTHOR Amarnath Murthy, Sep 09 2003 EXTENSIONS More terms from David Wasserman, May 25 2005 STATUS approved

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Last modified September 19 04:34 EDT 2024. Contains 376004 sequences. (Running on oeis4.)