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A365756
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G.f. satisfies A(x) = 1 + x*A(x) / (1 - x^3*A(x)^4).
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1
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1, 1, 1, 1, 2, 7, 22, 58, 142, 363, 1014, 2966, 8645, 24824, 71189, 206742, 609159, 1809493, 5388804, 16073002, 48092377, 144532884, 436168716, 1320372837, 4006489208, 12183544414, 37132838866, 113426618425, 347191793705, 1064688271730, 3270387354434
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OFFSET
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0,5
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LINKS
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FORMULA
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a(n) = Sum_{k=0..floor(n/3)} binomial(n-2*k-1,k) * binomial(n+k+1,n-3*k) / (n+k+1).
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PROG
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(PARI) a(n) = sum(k=0, n\3, binomial(n-2*k-1, k)*binomial(n+k+1, n-3*k)/(n+k+1));
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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