OFFSET
0,2
COMMENTS
A transform of 2^n by the Riordan array (1,x(1-x^2))^(-1).
(1/(1+x),x(1+2x)/(1+x)^3)^(-1) factors as (1,x(1-x^2))^(-1)*(1/(1-x),x/(1-x)).
Hankel transform is A138176.
FORMULA
G.f.: 1/(1-2v) where v=(2/sqrt(3))*sin(asin(x*3*sqrt(3)/2)/3), the reversion of x(1-x^2);
Conjecture: 12*n*(n-1)*(39*n-88)*a(n) -8*(n-1)*(156*n^2-352*n+27)*a(n-1) +9*(-351*n^3-2196*n^2-4325*n+2680)*a(n-2) +24*(39*n-49)*(3*n-7)*(3*n-8)*a(n-3)=0.- R. J. Mathar, Oct 25 2012
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Mar 03 2008
STATUS
approved