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A228079
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a(n) = round((5^n)*4 / 3^n).
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1
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4, 7, 11, 19, 31, 51, 86, 143, 238, 397, 662, 1103, 1838, 3063, 5104, 8507, 14179, 23631, 39386, 65643, 109404, 182341, 303901, 506502, 844170, 1406950, 2344917, 3908195, 6513658, 10856097, 18093496, 30155826, 50259710, 83766183, 139610306, 232683843
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OFFSET
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0,1
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COMMENTS
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The nearest integer of perimeter of Cross-Stitch Curve (fractal) after n-th iteration starting with a unit square.
The total side segments after n-th iteration is (5^n)*4.
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LINKS
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FORMULA
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EXAMPLE
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For n = 1, the total sides = 4 * 5 = 20, each side length = 1/3, the perimeter = 20 * 1/3 = 6.666..; a(1) = 7.
For n = 2, the total sides = 4 * 5^2 = 100, each side length = 1/9, the perimeter = 100 * 1/9 = 11.111..; a(2) = 11.
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PROG
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(MIT/GNU Scheme) (define (A228079 n) (round->exact (/ (* 4 (expt 5 n)) (expt 3 n)))) - Antti Karttunen, Aug 09 2013
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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