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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A115149 Tenth convolution of A115140. 10
1, -10, 35, -50, 25, -2, 0, 0, 0, 0, -1, -10, -65, -350, -1700, -7752, -33915, -144210, -600875, -2466750, -10015005, -40320150, -161280600, -641886000, -2544619500, -10056336264, -39645171810, -155989499540, -612815891050, -2404551645100, -9425842448792 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Because (x*c(x))^n + (1/c(x))^n = L(n,-x)= Sum_{k=0..floor(n/2)} A034807(n,k)*(-x)^k the sequence starts with the Lucas polynomial L(10,-x) (of degree 5).

LINKS

Seiichi Manyama, Table of n, a(n) for n = 0..1671

FORMULA

O.g.f.: 1/c(x)^10 = P(11, x) - x*P(10, x)*c(x) with the o.g.f. c(x):=(1-sqrt(1-4*x))/(2*x) of A000108 (Catalan numbers) and the polynomials P(n, x) defined in A115139. Here P(11, x) = 1 - 9*x + 28*x^2 - 35*x^3 + 15*x^4 - x^5 and P(10, x) = 1 - 8*x + 21*x^2 - 20*x^3 + 5*x^4.

a(n) = -C10(n-10), n >= 10, with C10(n) = (n+4) (eighth convolution of Catalan numbers). a(0)=1, a(1)=-10, a(2)=35, a(3)=-50, a(4)=25, a(5)=-2, a(6)=a(7)=a(8)=a(9)=0. [1, -10, 35, -50, 25, -2] is row n=10 of signed A034807 (signed Lucas polynomials).

a(n) ~ -5 * 2^(2*n - 10) / (sqrt(Pi) * n^(3/2)). - Vaclav Kotesovec, Feb 13 2019

MATHEMATICA

CoefficientList[Series[(1-10*x+35*x^2-50*x^3+25*x^4-2*x^5 +(1-8*x+21*x^2 -20*x^3+5*x^4)*Sqrt[1-4*x])/2, {x, 0, 30}], x] (* G. C. Greubel, Feb 12 2019 *)

PROG

(PARI) my(x='x+O('x^30)); Vec((1-10*x+35*x^2-50*x^3+25*x^4-2*x^5 +(1-8*x +21*x^2 -20*x^3+5*x^4)*sqrt(1-4*x))/2) \\ G. C. Greubel, Feb 12 2019

(MAGMA) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); Coefficients(R!( (1-10*x+35*x^2-50*x^3+25*x^4-2*x^5 +(1-8*x+21*x^2 -20*x^3+5*x^4 )*Sqrt(1-4*x))/2 )); // G. C. Greubel, Feb 12 2019

(Sage) ((1-10*x+35*x^2-50*x^3+25*x^4-2*x^5 +(1-8*x+21*x^2 -20*x^3+5*x^4) *sqrt(1-4*x))/2).series(x, 30).coefficients(x, sparse=False) # G. C. Greubel, Feb 12 2019

CROSSREFS

Cf. A115139 - A115148.

Sequence in context: A010818 A243939 A065195 * A044087 A022702 A044468

Adjacent sequences:  A115146 A115147 A115148 * A115150 A115151 A115152

KEYWORD

sign,easy

AUTHOR

Wolfdieter Lang, Jan 13 2006

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 20 14:19 EDT 2019. Contains 325185 sequences. (Running on oeis4.)