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A081338
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a(n) = (9^n + 5^n)/2.
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2
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1, 7, 53, 427, 3593, 31087, 273533, 2430547, 21718673, 194686807, 1748275013, 15714943867, 141336838553, 1271543265727, 11441447985293, 102960824836387, 926586388371233, 8338972319559847, 75049224997132373, 675435395579660107
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OFFSET
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0,2
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COMMENTS
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Binomial transform of A081337. 7th binomial transform of (1,0,4,0,16,0,64,....).
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LINKS
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FORMULA
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a(n) = 14*a(n-1)-45*a(n-2), a(0)=1, a(1)=7.
G.f.: (1-7*x)/((1-5*x)*(1-9*x)).
E.g.f.: exp(7*x) * cosh(2*x).
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MATHEMATICA
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CoefficientList[Series[(1 - 7 x) / ((1 - 5 x) (1 - 9 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Aug 08 2013 *)
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PROG
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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