OFFSET
0,3
COMMENTS
LINKS
Paul D. Hanna, Table of n, a(n) for n = 0..1024
EXAMPLE
G.f.: A(x) = 1 + x + 4*x^2 + 19*x^3 + 92*x^4 + 446*x^5 + 2150*x^6 + 10280*x^7 + 48761*x^8 + 229558*x^9 + 1073278*x^10 + 4986624*x^11 + 23037102*x^12 +...
where
A(x)^2 = 1 + 2*x + 9*x^2 + 46*x^3 + 238*x^4 + 1228*x^5 + 6289*x^6 + 31924*x^7 + 160694*x^8 + 802642*x^9 + 3980916*x^10 +...+ A274965(2*n)*x^n +...
PROG
(PARI) {a(n) = my(A, B=1); for(k=0, 2*n, B = B^2 + x^(2*n+1-k) +O(x^(2*n+1))); A = sqrt( (B + subst(B, x, -x))/2 ); polcoeff(A, 2*n)}
for(n=0, 30, print1(a(n), ", "))
CROSSREFS
KEYWORD
sign
AUTHOR
Paul D. Hanna, Aug 14 2016
STATUS
approved