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A320469
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a(n) = 3*a(n-1) + 10*a(n-2), n >= 2; a(0)=1, a(1)=1.
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2
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1, 1, 13, 49, 277, 1321, 6733, 33409, 167557, 836761, 4185853, 20925169, 104634037, 523153801, 2615801773, 13078943329, 65394847717, 326973976441, 1634870406493, 8174350983889, 40871757016597, 204358780888681, 1021793912832013, 5108969547382849, 25544847770468677
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OFFSET
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0,3
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LINKS
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FORMULA
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a(n) = (4*(-2)^n + 3*5^n)/7.
G.f.: (1-2*x)/((1-5*x)*(1+2*x)).
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PROG
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(PARI) {a(n) = (4*(-2)^n+3*5^n)/7}
(PARI) N=40; x='x+O('x^N); Vec((1-2*x)/((1-5*x)*(1+2*x)))
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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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STATUS
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approved
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