login
This site is supported by donations to The OEIS Foundation.

 

Logo

The submissions stack has been unacceptably high for several months now. Please voluntarily restrict your submissions and please help with the editing. (We don't want to have to impose further limits.)

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A131926 Expansion of series reversion of x(1-7x)/(1-x) . 2

%I

%S 1,6,78,1266,23010,448062,9140118,192804954,4171347258,92051810934,

%T 2063947865694,46885775086338,1076785174781394,24959959877000238,

%U 583201632981980454,13721408509737851754,324797812150741560618,7729580015834558984934,184829586432121709114478

%N Expansion of series reversion of x(1-7x)/(1-x) .

%C The Hankel transform of this sequence is 42^C(n+1,2) .

%F a(n) = Sum_{k, 0<=k<=n}A086810(n,k)*6^k .

%F From _Vaclav Kotesovec_, Aug 20 2013: (Start)

%F G.f.: (x-13-sqrt(x^2-26*x+1))/14.

%F Recurrence: n*a(n) = 13*(2*n-3)*a(n-1) - (n-3)*a(n-2).

%F a(n) ~ sqrt(13*sqrt(42)-84)*(13+2*sqrt(42))^n/(14*sqrt(Pi)*n^(3/2)). (End)

%t Rest[CoefficientList[InverseSeries[Series[x*(1-7*x)/(1-x),{x,0,20}],x],x]] (* _Vaclav Kotesovec_, Aug 20 2013 *)

%o (PARI) Vec(serreverse(x*(1-7*x)/(1-x)+O(x^66))) /* _Joerg Arndt_, Feb 06 2013 */

%K nonn

%O 1,2

%A _Philippe Deléham_, Oct 29 2007

%E More terms from _Philippe Deléham_, Feb 06 2013

%E Offset corrected, _Joerg Arndt_, Feb 15 2013

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified August 28 08:35 EDT 2015. Contains 261118 sequences.