OFFSET
0,6
LINKS
Dmitry Kruchinin, Vladimir Kruchinin, Method for solving an iterative functional equation $A^{2^n}(x)=F(x)$, arXiv:1302.1986
FORMULA
a(n) = numerator(T(n,1)); T(n,m) = if n=m then 1 else 1/2*(((-1)^m*2^m*((-1)^(n+m)+1)*sum(j=1..m, ((sum(i=0..(j-1)/2,(j-2*i)^(n+m) *C(j,i))) *C(m,j) *(-1)^((n+m)/2+m-j))/2^j))/(n+m)! -sum(i=m+1..n-1, T(n,i) *T(i,m))).
EXAMPLE
x - 1/24*x^3 - 7/5760*x^5 - 23/193536*x^7 - 5947/464486400*x^9 + ...
CROSSREFS
KEYWORD
sign
AUTHOR
Vladimir Kruchinin, Nov 12 2011
STATUS
approved