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A133469
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a(n) = a(n-1) + 7*a(n-2) for n >= 2, a(0)=1, a(1)=2.
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3
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1, 2, 9, 23, 86, 247, 849, 2578, 8521, 26567, 86214, 272183, 875681, 2780962, 8910729, 28377463, 90752566, 289394807, 924662769, 2950426418, 9423065801, 30076050727, 96037511334, 306569866423, 978832445761, 3124821510722
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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+x)/(1-x-7*x^2) .
a(n) = ((29 + 3*sqrt(29))/58)*(0.5 + 0.5*sqrt(29))^n + ((29 - 3*sqrt(29))/58)*(0.5 - 0.5*sqrt(29))^n. - Richard Choulet, Nov 20 2008
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MAPLE
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f:= gfun:-rectoproc({a(n) = a(n-1) + 7*a(n-2), a(0)=1, a(1)=2}, a(n), remember):
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MATHEMATICA
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LinearRecurrence[{1, 7}, {1, 2}, 30] (* Harvey P. Dale, Dec 09 2013 *)
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PROG
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(PARI) x='x+O('x^99); Vec((1+x)/(1-x-7*x^2)) \\ Altug Alkan, Jul 23 2017
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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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