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A179337
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Positive integers of the form (6*m^2 + 1)/11.
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6
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5, 35, 107, 197, 341, 491, 707, 917, 1205, 1475, 1835, 2165, 2597, 2987, 3491, 3941, 4517, 5027, 5675, 6245, 6965, 7595, 8387, 9077, 9941, 10691, 11627, 12437, 13445, 14315, 15395, 16325, 17477, 18467, 19691, 20741, 22037, 23147, 24515
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OFFSET
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1,1
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COMMENTS
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Here m = (11*(2*n-1) - (-1)^n)/4 for n > 0.
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LINKS
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FORMULA
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a(n) = (66*n*(n-1) - 3*(2*n-1)*(-1)^n + 17)/4.
G.f.: x*(5 + 30*x + 62*x^2 + 30*x^3 + 5*x^4)/((1+x)^2*(1-x)^3).
a(n) = a(-n+1) = a(n-1) + 2*a(n-2) - 2*a(n-3) - a(n-4) + a(n-5).
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MATHEMATICA
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LinearRecurrence[{1, 2, -2, -1, 1}, {5, 35, 107, 197, 341}, 40] (* Vincenzo Librandi, Nov 16 2011 *)
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PROG
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(Magma) [(66*n*(n-1)-3*(2*n-1)*(-1)^n+17)/4: n in [1..40]]; // Vincenzo Librandi, Nov 16 2011
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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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