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A141495
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a(n) = 3*a(n-1) for n>2; a(0)=1, a(1)=3, a(2)=7.
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3
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1, 3, 7, 21, 63, 189, 567, 1701, 5103, 15309, 45927, 137781, 413343, 1240029, 3720087, 11160261, 33480783, 100442349, 301327047, 903981141, 2711943423, 8135830269, 24407490807, 73222472421, 219667417263, 659002251789
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OFFSET
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0,2
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COMMENTS
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A sequence of the form: a(0)=1, a(1)=prime(m), a(2)=prime(m+2), a(n)=a(1)*a(n-1).
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LINKS
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FORMULA
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a(n) = 7*3^(n-2) for n>1. a(n)=3*a(n-1) for n>2. G.f.: (2*x^2-1) / (3*x-1). - Colin Barker, Jan 09 2014
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MATHEMATICA
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a[0] = 1; a[1] = 3; a[2] = 7; a[n_] := a[n] = a[1]*a[n - 1]; Table[a[n], {n, 0, 30}]
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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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STATUS
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approved
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