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A355492
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a(n) = 7*3^n - 2.
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1
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5, 19, 61, 187, 565, 1699, 5101, 15307, 45925, 137779, 413341, 1240027, 3720085, 11160259, 33480781, 100442347, 301327045, 903981139, 2711943421, 8135830267, 24407490805, 73222472419, 219667417261, 659002251787, 1977006755365, 5931020266099, 17793060798301, 53379182394907
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OFFSET
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0,1
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COMMENTS
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Right ending points of the gaps in A171884. The left ending points are given in A198643.
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LINKS
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FORMULA
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G.f.: (5-x)/((1-x)*(1-3*x)).
E.g.f.: 7*exp(3*x) - 2*exp(x).
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EXAMPLE
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The numbers not appearing in A171884 are those in the range [5*3^k-1, 7*3^k-2] for some k; that is, [4, 5] U [14, 19] U [44, 61] U ...
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PROG
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(PARI) a(n)=7*3^n-2
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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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