A106224 Coefficients of g.f. A(x) where 0 <= a(n) <= 5 for all n>1, with initial terms {1,6}, such that A(x)^(1/6) consists entirely of integer coefficients.
1, 6, 3, 2, 3, 0, 0, 0, 3, 4, 3, 0, 0, 0, 3, 2, 0, 0, 0, 0, 3, 2, 0, 0, 4, 0, 0, 2, 0, 0, 2, 0, 0, 0, 3, 0, 3, 0, 0, 4, 0, 0, 4, 0, 0, 4, 3, 0, 2, 0, 0, 4, 0, 0, 5, 0, 3, 2, 0, 0, 3, 0, 0, 0, 3, 0, 3, 0, 3, 0, 3, 0, 2, 0, 3, 0, 0, 0, 2, 0, 0, 0, 3, 0, 2, 0, 0, 0, 3, 0, 5, 0, 3, 0, 0, 0, 3, 0, 0, 0, 0, 0, 4, 0, 0
Offset: 0
Keywords
Examples
A(x) = 1 + 6*x + 3*x^2 + 2*x^3 + 3*x^4 + 3*x^8 + 4*x^9 + 3*x^10 +...
A(x)^(1/6) = 1 + x - 2*x^2 + 7*x^3 - 27*x^4 + 114*x^5 - 506*x^6 +-...
A106225 = {1,1,-2,7,-27,114,-506,2322,-10919,52316,-254369,...}.
Programs
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PARI
{a(n)=local(A=1+6*x);if(n==0,1, for(j=1,n, for(k=0,5,t=polcoeff((A+k*x^j+x*O(x^j))^(1/6),j); if(denominator(t)==1,A=A+k*x^j;break))); return(polcoeff(A+x*O(x^n),n)))}
Formula
A(z)=0 at z=-0.18172379526003557530948965401615522817...
Comments