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A047317
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Numbers that are congruent to {1, 2, 4, 5, 6} mod 7.
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1
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1, 2, 4, 5, 6, 8, 9, 11, 12, 13, 15, 16, 18, 19, 20, 22, 23, 25, 26, 27, 29, 30, 32, 33, 34, 36, 37, 39, 40, 41, 43, 44, 46, 47, 48, 50, 51, 53, 54, 55, 57, 58, 60, 61, 62, 64, 65, 67, 68, 69, 71, 72, 74, 75, 76, 78, 79
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n) = a(n-1) + a(n-5) - a(n-6).
G.f.: x*(1 + x + 2*x^2 + x^3 + x^4 + x^5) / ( (x^4 + x^3 + x^2 + x + 1)*(x-1)^2 ). - R. J. Mathar, Dec 03 2011
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MATHEMATICA
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CoefficientList[Series[(1 + x + 2 x^2 + x^3 + x^4 + x^5) / ((x^4 + x^3 + x^2 + x + 1) (x - 1)^2), {x, 0, 60}], x] (* Vincenzo Librandi, Jul 26 2013 *)
LinearRecurrence[{1, 0, 0, 0, 1, -1}, {1, 2, 4, 5, 6, 8}, 100] (* Harvey P. Dale, Apr 02 2017 *)
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PROG
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(Magma) [n: n in [1..80] | n mod 7 in [1, 2, 4, 5, 6]]; // Vincenzo Librandi, Jul 26 2013
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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