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A193353
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G.f. satisfies: A(x) = Sum_{n>=0} x^n * Product_{k=1..n} A(k*x)/(1+k*x).
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0
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1, 1, 1, 2, 7, 30, 197, 1770, 22536, 409456, 10541949, 387914810, 20362048664, 1525681168956, 163330533908217, 24973901010606886, 5456672750531017964, 1704092792275195175172, 760753610853139920737328, 485646261179496433286709024
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OFFSET
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0,4
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LINKS
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EXAMPLE
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G.f.: A(x) = 1 + x + x^2 + 2*x^3 + 7*x^4 + 30*x^5 + 197*x^6 + 1770*x^7 +...
where
A(x) = 1 + x*A(x)/(1+x) + x^2*A(x)*A(2*x)/((1+x)*(1+2*x)) + x^3*A(x)*A(2*x)*A(3*x)/((1+x)*(1+2*x)*(1+3*x)) +...
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PROG
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(PARI) {a(n)=local(A=1+x); for(i=1, n, A=sum(m=0, n, x^m*prod(k=1, m, subst(A, x, k*x)/(1+k*x+x*O(x^n))))); polcoeff(A, n)}
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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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