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A107101
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Denominators of coefficients in g.f. that satisfies: [x^n] A(x)^(1/n) = 0 for all n>1, with a(0)=a(1)=1.
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2
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1, 1, 4, 54, 4608, 10800000, 233280000, 213462345600000, 71945836874956800000, 301100369020478344396800000, 3345559655783092715520000000000, 42953724653410633055099209541222400000000
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OFFSET
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0,3
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LINKS
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FORMULA
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EXAMPLE
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A(x) = 1 + x + 1/4*x^2 - 1/54*x^3 - 19/4608*x^4 +-...
A(x)^(1/2) = 1 + 1/2*x + 0*x^2 - 1/108*x^3 + 71/27648*x^4 -+...
A(x)^(1/3) = 1 + 1/3*x - 1/36*x^2 + 0*x^3 + 13/13824*x^4 -+...
A(x)^(1/4) = 1 + 1/4*x - 1/32*x^2 + 11/3456*x^3 + 0*x^4 -+...
Initial coefficients of A(x) are:
-64667/233280000, 1752946877/213462345600000,
796654376069593/71945836874956800000,
-1318782726516512640001/301100369020478344396800000,
3482456481351141439684019/3345559655783092715520000000000, ...}.
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PROG
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(PARI) {a(n)=local(A=1+x+x^2*O(x^n), C, D); for(k=2, n+1, C=polcoeff((A+t*x^k)^(1/k), k, x); D=(0-subst(C, t, 0))/(subst(C, t, 1)-subst(C, t, 0)); A=A+D*x^k); denominator(polcoeff(A, n))}
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CROSSREFS
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KEYWORD
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frac,nonn
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AUTHOR
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STATUS
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approved
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