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A368456
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Number of independent vertex sets in the n-Dorogovtsev-Goltsev-Mendes graph.
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2
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OFFSET
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0,1
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COMMENTS
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Using the indexing convention that DGM(0) = P_2.
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LINKS
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FORMULA
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a(n) = b(n) + 2*c(n) where b(0) = c(0) = 1 and c(n) = b(n-1)*c(n-1)^2, b(n) = c(n) + b(n-1)^3 for n > 0. - Andrew Howroyd, Dec 30 2023
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PROG
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(PARI) a(n) = {my(b=1, c=1); for(k=1, n, c = b*c^2; b = b^3 + c); b + 2*c} \\ Andrew Howroyd, Dec 30 2023
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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a(0) prepended and terms a(5) and beyond from Andrew Howroyd, Dec 30 2023
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STATUS
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approved
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