A107088 G.f. A(x) satisfies: A(x) = A(x^2)^(1/2) + 4*x.

1, 4, 2, 0, -1, 0, 2, 0, -5, 0, 12, 0, -30, 0, 82, 0, -233, 0, 668, 0, -1949, 0, 5802, 0, -17503, 0, 53302, 0, -163783, 0, 507418, 0, -1582869, 0, 4966790, 0, -15667573, 0, 49658264, 0, -158059506, 0, 505013014, 0, -1619144976, 0, 5207596574, 0, -16797286048, 0, 54323516786, 0, -176113786590, 0

Offset: 0

Author

Paul D. Hanna, May 11 2005

Keywords

• sign

Comments

Self-convolution 4th power of A107086. Self-convolution of A107087.

Examples

			A(x) = 1 + 4*x + 2*x^2 - x^4 + 2*x^6 - 5*x^8 + 12*x^10 - 30*x^12 +...
A(x^2)^(1/2) = 1 + 2*x^2 - x^4 + 2*x^6 - 5*x^8 + 12*x^10 - 30*x^12 +...
		

Crossrefs

Cf. A107086, A107087.

Programs

PARI

{a(n)=local(A=1+x);for(i=1,n,A=subst(A,x,x^2)^(1/2)+4*x+x*O(x^n)); polcoeff(A,n,x)}