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A367115
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G.f. satisfies A(x) = 1 + 2*x*A(x) + 2*x^4*A(x)^4.
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2
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1, 2, 4, 8, 18, 52, 184, 688, 2512, 8864, 30784, 107648, 384432, 1403872, 5205568, 19443328, 72817856, 273199488, 1027939072, 3883718144, 14741042464, 56189409088, 214931447680, 824443822848, 3169934397184, 12214858010112, 47168251137024
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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) = Sum_{k=0..floor(n/4)} 2^(n-3*k) * binomial(n,4*k) * A002293(k).
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PROG
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(PARI) a(n) = sum(k=0, n\4, 2^(n-3*k)*binomial(n, 4*k)*binomial(4*k, k)/(3*k+1));
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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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