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A088439
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a(3n) = 3n, otherwise a(n) = 1.
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2
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0, 1, 1, 3, 1, 1, 6, 1, 1, 9, 1, 1, 12, 1, 1, 15, 1, 1, 18, 1, 1, 21, 1, 1, 24, 1, 1, 27, 1, 1, 30, 1, 1, 33, 1, 1, 36, 1, 1, 39, 1, 1, 42, 1, 1, 45, 1, 1, 48, 1, 1, 51, 1, 1, 54, 1, 1, 57, 1, 1, 60, 1, 1, 63, 1, 1, 66, 1, 1, 69, 1, 1, 72, 1, 1, 75, 1, 1, 78, 1, 1, 81, 1, 1, 84, 1, 1, 87, 1, 1, 90, 1, 1
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OFFSET
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0,4
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LINKS
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FORMULA
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G.f.: x*(1+x+3*x^2-x^3-x^4)/(1-x^3)^2.
E.g.f.: (1/3)*(x+2)*exp(x) - (2/3)*exp(-x/2)*( cos(sqrt(3)*x/2) + x*sin((Pi + 3*sqrt(3)*x)/6) ). - G. C. Greubel, Dec 05 2022
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MATHEMATICA
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Table[If[Divisible[n, 3], n, 1], {n, 0, 100}] (* or *) LinearRecurrence[ {0, 0, 2, 0, 0, -1}, {0, 1, 1, 3, 1, 1}, 100] (* Harvey P. Dale, Jun 18 2018 *)
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PROG
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(Magma) [n mod 3 eq 0 select n else 1: n in [0..100]]; // Bruno Berselli, Mar 11 2011
(SageMath)
def A088439(n): return 1 if (n%3) else n
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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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