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A367691
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G.f. A(x) satisfies A(x) = 1 / ((1 - x) * (1 - x * A(x^3))).
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3
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1, 2, 3, 4, 7, 12, 19, 31, 52, 86, 141, 233, 386, 639, 1057, 1749, 2896, 4795, 7937, 13138, 21751, 36010, 59613, 98688, 163380, 270479, 447779, 741300, 1227231, 2031697, 3363494, 5568295, 9218373, 15261119, 25264942, 41826373, 69244006, 114634194, 189778123
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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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a(n) = 1 + Sum_{k=0..floor((n-1)/3)} a(k) * a(n-1-3*k).
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PROG
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(PARI) a_vector(n) = my(v=vector(n+1)); for(i=0, n, v[i+1]=1+sum(j=0, (i-1)\3, v[j+1]*v[i-3*j])); v;
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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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