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A186948
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a(n) = 3^n - 2*n.
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3
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1, 1, 5, 21, 73, 233, 717, 2173, 6545, 19665, 59029, 177125, 531417, 1594297, 4782941, 14348877, 43046689, 129140129, 387420453, 1162261429, 3486784361, 10460353161, 31381059565, 94143178781, 282429536433, 847288609393
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OFFSET
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0,3
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COMMENTS
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LINKS
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FORMULA
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G.f.: (1 - 4x + 7x^2)/((1-x)^2*(1-3x)).
a(n) = 5*a(n-1) - 7*a(n-2) + 3*a(n-3); a(0)=1, a(1)=1, a(2)=5. - Harvey P. Dale, Nov 24 2011
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MATHEMATICA
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Table[3^n-2n, {n, 0, 30}] (* or *) LinearRecurrence[{5, -7, 3}, {1, 1, 5}, 30] (* Harvey P. Dale, Nov 24 2011 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,easy,changed
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AUTHOR
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STATUS
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approved
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