login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A107095 G.f. satisfies: A(A(x)) = (1+x)^2*A(x). 2

%I #7 May 03 2012 13:04:29

%S 0,1,2,-3,18,-150,1518,-17541,223782,-3087948,45470022,-707810715,

%T 11569008816,-197540043324,3509923686678,-64697804055675,

%U 1234127209128306,-24312707152663590,493834352052852738,-10327320248199824889,222086739445484152590

%N G.f. satisfies: A(A(x)) = (1+x)^2*A(x).

%F G.f. A(x) = G(x)^2/x where G(x) is g.f. of A107096.

%F a(n)=T(n,1), T(n,m)=sum(i=1..n-m, binomial(2*m,i)*T(n-i,m))-sum(k=m+1..n-1, T(n,k)*T(k,m)), n>m, T(n,n)=1. [_Vladimir Kruchinin_ May 03 2012]

%o (PARI) {a(n)=local(A,B,F);if(n<1,0,F=x+2*x^2+x*O(x^n);A=F; for(j=0,n, for(i=0,j,B=serreverse(A);A=(A+subst(B,x,A*(1+x)^2))/2); A=round(A));polcoeff(A,n,x))}

%o (Maxima) T(n,m):=if n=m then 1 else sum(binomial(2*m,i)*T(n-i,m),i,1,n-m)-sum(T(n,k)*T(k,m),k,m+1,n-1); makelist(T(n,1),n,1,10); [_Vladimir Kruchinin_ May 03 2012]

%Y Cf. A107096.

%K sign

%O 0,3

%A _Paul D. Hanna_, May 12 2005

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)