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A067980
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Convolution of L(n+1) := A000204(n+1) (Lucas), n>=0, with L(n+2), n>=0.
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2
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3, 13, 31, 69, 140, 274, 519, 963, 1757, 3165, 5642, 9972, 17499, 30521, 52955, 91461, 157336, 269702, 460863, 785295, 1334713, 2263293, 3829846, 6468264, 10905075, 18355429, 30849559, 51776133, 86785892
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OFFSET
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0,1
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COMMENTS
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Second diagonal of triangle A067979. Second column of triangle A067990.
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LINKS
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FORMULA
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a(n)= sum(L(k+1)*L(n+2-k), k=0..n) = (4*n+3)*F(n+1)+3*(n+1)*F(n), with F(n) := A000045(n) (Fibonacci).
G.f.: (3+x)*(1+2*x)/(1-x-x^2)^2.
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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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