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0, 0, 0, 1, -2, 4, -7, 13, -24, 48, -99, 221, -512, 1268, -3247, 8773, -24400, 70896, -211347, 653541, -2068472, 6755684, -22541135, 77305981, -270435640, 969413776, -3539893923, 13212871629, -50180362320, 194412817844, -765590169935, 3070433223317
(list;
graph;
refs;
listen;
history;
text;
internal format)
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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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G.f. satisfies: A(x) = x^3*((2+x)/(1+x) + (1+x)*A'(x))/(2+3*x+2*x^2). a(n+3) = (-1)^n*Sum_{k=0..n} Sum{j=0..[k/2]} (k-j)!/(k-2*j)! for n>=0. a(n+3) = -a(n+2) + (-1)^n*A072374(n) for n>=1.
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PROG
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(PARI) a(n)=if(n<3, 0, (-1)^(n-3)*sum(k=0, n-3, sum(j=0, k\2, (k-j)!/(k-2*j)!)))
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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