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A113804
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Numbers that are congruent to 4 or 10 mod 14.
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10
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4, 10, 18, 24, 32, 38, 46, 52, 60, 66, 74, 80, 88, 94, 102, 108, 116, 122, 130, 136, 144, 150, 158, 164, 172, 178, 186, 192, 200, 206, 214, 220, 228, 234, 242, 248, 256, 262, 270, 276, 284, 290, 298, 304, 312, 318, 326, 332, 340, 346, 354, 360
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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a(n) = 7n - ((-1)^n + 7)/2.
G.f.: 2x*(2 + 3x + 2x^2)/((1-x)^2*(1+x)). (End)
Sum_{n>=1} (-1)^(n+1)/a(n) = tan(3*Pi/14)*Pi/14. - Amiram Eldar, Dec 30 2021
E.g.f.: 4 + ((14*x - 7)*exp(x) - exp(-x))/2. - David Lovler, Sep 04 2022
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MATHEMATICA
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Select[Range[2, 400, 2], MemberQ[{4, 10}, Mod[#, 14]]&] (* or *) LinearRecurrence[{1, 1, -1}, {4, 10, 18}, 60] (* Harvey P. Dale, Jan 08 2023 *)
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PROG
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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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EXTENSIONS
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More terms from Neven Juric, Apr 10 2008
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STATUS
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approved
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