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A120598
G.f. satisfies: 30*A(x) = 29 + 125*x + A(x)^5, starting with [1,5,10].
2
1, 5, 10, 90, 825, 8445, 92820, 1066740, 12670635, 154308775, 1916370170, 24177471370, 309007779015, 3992428316835, 52059968802000, 684240882022800, 9055282215370050, 120563388411386850, 1613785688724362400
OFFSET
0,2
COMMENTS
See comments in A120588 for conditions needed for an integer sequence to satisfy a functional equation of the form: r*A(x) = c + b*x + A(x)^n.
FORMULA
G.f.: A(x) = 1 + Series_Reversion((1+30*x - (1+x)^5)/125). Lagrange Inversion yields: G.f.: A(x) = Sum_{n>=0} C(5*n,n)/(4*n+1) * (29+125*x)^(4*n+1)/30^(5*n+1). - Paul D. Hanna, Jan 24 2008
a(n) ~ 5^(-1/2 + 3*n) * (-29 + 24*6^(1/4))^(1/2 - n) / (2^(15/8) * 3^(3/8) * n^(3/2) * sqrt(Pi)). - Vaclav Kotesovec, Nov 28 2017
EXAMPLE
A(x) = 1 + 5*x + 10*x^2 + 90*x^3 + 825*x^4 + 8445*x^5 +...
A(x)^5 = 1 + 25*x + 300*x^2 + 2700*x^3 + 24750*x^4 + 253350*x^5 +...
MATHEMATICA
CoefficientList[1 + InverseSeries[Series[(1+30*x - (1+x)^5)/125, {x, 0, 20}], x], x] (* Vaclav Kotesovec, Nov 28 2017 *)
PROG
(PARI) {a(n)=local(A=1+5*x+10*x^2+x*O(x^n)); for(i=0, n, A=A+(-30*A+29+125*x+A^5)/25); polcoeff(A, n)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jun 16 2006
STATUS
approved