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A027387
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Write digits for n, count endpoints (version 2).
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3
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0, 2, 2, 2, 4, 2, 1, 2, 0, 1, 2, 4, 4, 4, 6, 4, 3, 4, 2, 3, 2, 4, 4, 4, 6, 4, 3, 4, 2, 3, 2, 4, 4, 4, 6, 4, 3, 4, 2, 3, 4, 6, 6, 6, 8, 6, 5, 6, 4, 5, 2, 4, 4, 4, 6, 4, 3, 4, 2, 3, 1, 3, 3, 3, 5, 3, 2, 3, 1, 2, 2, 4, 4, 4, 6, 4, 3, 4, 2, 3, 0
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OFFSET
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0,2
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COMMENTS
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Number of endpoints: 0,8 - zero, 6,9 - one, 1,2,3,5,7 - two, 4 - four. - Michael B. Porter, Oct 28 2017
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LINKS
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FORMULA
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a(10*n + d) = a(n) + e where e is the number of endpoints of single digit d. - David A. Corneth, Oct 28 2017
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EXAMPLE
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The digit 1 has two endpoints, and the digit 8 has no endpoints, so a(18) = 2. - Michael B. Porter, Oct 28 2017
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PROG
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(PARI) a(n)=vecsum(apply(d->[0, 2, 2, 2, 4, 2, 1, 2, 0, 1][d+1], digits(n))); \\ based on program for A027386 by Andrew Howroyd, Michael B. Porter, Oct 26 2017
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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