A120596 G.f. satisfies: 6*A(x) = 5 + x + A(x)^5, starting with [1,1,10].

1, 1, 10, 210, 5505, 161601, 5082420, 167451780, 5705082795, 199354509755, 7105393162010, 257312347583330, 9440808323869455, 350189693739455535, 13110655796699158800, 494772468434359266960, 18801468275832345890970

Offset

0,3

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.

Links

Table of n, a(n) for n=0..16.

Formula

G.f.: A(x) = 1 + Series_Reversion(1+6*x - (1+x)^5). Lagrange Inversion yields: G.f.: A(x) = Sum_{n>=0} C(5*n,n)/(4*n+1) * (5+x)^(4*n+1)/6^(5*n+1). - Paul D. Hanna, Jan 24 2008

a(n) ~ (-5 + 4*(6/5)^(5/4))^(1/2 - n) / (2^(15/8) * 3^(3/8) * 5^(1/8) * n^(3/2) * sqrt(Pi)). - Vaclav Kotesovec, Nov 28 2017

Example

A(x) = 1 + x + 10*x^2 + 210*x^3 + 5505*x^4 + 161601*x^5 +...
A(x)^5 = 1 + 5*x + 60*x^2 + 1260*x^3 + 33030*x^4 + 969606*x^5 +...

Mathematica

CoefficientList[1 + InverseSeries[Series[1+6*x - (1+x)^5, {x, 0, 20}], x], x] (* Vaclav Kotesovec, Nov 28 2017 *)

Prog

(PARI) {a(n)=local(A=1+x+10*x^2+x*O(x^n)); for(i=0, n, A=A-6*A+5+x+A^5); polcoeff(A, n)}

Crossrefs

Cf. A120588 - A120595, A120597 - A120607.

Sequence in context: A052246 A001450 A076803 * A238467 A254322 A365341

Adjacent sequences: A120593 A120594 A120595 * A120597 A120598 A120599

Keyword

nonn

Author

Paul D. Hanna, Jun 16 2006

Status

approved