OFFSET
0,3
COMMENTS
a(n) = A261885(n)/3.
LINKS
Paul D. Hanna, Table of n, a(n) for n = 0..200
EXAMPLE
E.g.f.: A(x) = x - 2*x^2/2! + 11*x^3/3! - 96*x^4/4! + 1080*x^5/5! - 13776*x^6/6! + 179592*x^7/7! - 2257536*x^8/8! + 36167616*x^9/9! - 1328400000*x^10/10! +...
A(x/(1-x)^3) = x + 4*x^2/2! + 11*x^3/3! + 36*x^4/4! + 300*x^5/5! + 984*x^6/6! - 6384*x^7/7! + 564864*x^8/8! + 615744*x^9/9! - 598890240*x^10/10! +...
where A(x/(1-x)^3) = (1+2*x)/(1-x)*A(x).
PROG
(PARI) /* E.g.f. satisfies: A(x) = (1-x)/(1+2*x)*A(x/(1-x)^3): */
{a(n)=local(A=x, B); for(m=2, n, B=(1-x)/(1+2*x+O(x^(n+3)))*subst(A, x, x/(1-x+O(x^(n+3)))^3); A=A-polcoeff(B, m+1)*x^m/(m-1)/3); n!*polcoeff(A, n)}
for(n=0, 20, print1(a(n), ", "))
CROSSREFS
KEYWORD
sign
AUTHOR
Paul D. Hanna, Sep 04 2015
STATUS
approved