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1, 12, 84, 558, 3696, 24582, 164304, 1103478, 7444416, 50431302, 342941424, 2340123798, 16018069536, 109949704422, 756587236944, 5217746494518, 36054040477056, 249557173431942, 1729973554578864, 12008254925383638
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OFFSET
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0,2
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LINKS
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FORMULA
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G.f.: 1/(1-7*x)+1/(1-6*x)-1/(1-x). E.g.f.: e^(7*x)+e^(6*x)-e^x.
a(0)=1, a(1)=12, a(2)=84, a(n)=14*a(n-1)-55*a(n-2)+42*a(n-3) [From Harvey P. Dale, May 08 2012]
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MATHEMATICA
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Table[7^n+6^n-1, {n, 0, 20}] (* or *) LinearRecurrence[{14, -55, 42}, {1, 12, 84}, 20] (* Harvey P. Dale, May 08 2012 *)
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PROG
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CROSSREFS
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Cf. A155628, A155629, A155630, A155631, A155632, A155633, A155634, A155635, A155636, A155637, A155638, A155639, A155640, A155641, A155642, A155643, A155644.
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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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