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A213104
G.f. satisfies: A(x) = 1 + x/A(-x*A(x)^10)^5.
17
1, 1, 5, 40, 360, 3820, 43651, 543240, 7146185, 98885725, 1420274645, 21037156031, 319127602075, 4935547265370, 77525696636995, 1233356748777015, 19829269320322346, 321631227310756885, 5255920261950786655, 86436636022328320125, 1429253483704685851315
OFFSET
0,3
COMMENTS
Compare definition of g.f. to:
(1) B(x) = 1 + x/B(-x*B(x)) when B(x) = 1/(1-x).
(2) C(x) = 1 + x/C(-x*C(x)^3)^2 when C(x) = 1 + x*C(x)^2 (A000108).
(3) D(x) = 1 + x/D(-x*D(x)^5)^3 when D(x) = 1 + x*D(x)^3 (A001764).
(4) E(x) = 1 + x/E(-x*E(x)^7)^4 when E(x) = 1 + x*E(x)^4 (A002293).
(5) F(x) = 1 + x/F(-x*F(x)^9)^5 when F(x) = 1 + x*F(x)^5 (A002294).
(6) G(x) = 1 + x/G(-x*G(x)^11)^6 when G(x) = 1 + x*G(x)^6 (A002295).
The first negative term is a(306). - Georg Fischer, Feb 16 2019
LINKS
EXAMPLE
G.f.: A(x) = 1 + x + 5*x^2 + 40*x^3 + 360*x^4 + 3820*x^5 + 43651*x^6 +...
Related expansions:
A(x)^10 = 1 + 10*x + 95*x^2 + 970*x^3 + 10335*x^4 + 116452*x^5 +...
A(-x*A(x)^10)^5 = 1 - 5*x - 15*x^2 - 85*x^3 - 995*x^4 - 10776*x^5 -...
MATHEMATICA
m = 21; A[_] = 1; Do[A[x_] = 1 + x/A[-x A[x]^10]^5 + O[x]^m, {m}];
CoefficientList[A[x], x] (* Jean-François Alcover, Nov 06 2019 *)
PROG
(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(i=1, n, A=1+x/subst(A^5, x, -x*subst(A^10, x, x+x*O(x^n))) ); polcoeff(A, n)}
for(n=0, 30, print1(a(n), ", "))
KEYWORD
sign
AUTHOR
Paul D. Hanna, Jun 05 2012
STATUS
approved