A275751 Self-convolution square root of the even bisection of A274965.

1, 1, 4, 19, 92, 446, 2150, 10280, 48761, 229558, 1073278, 4986624, 23037102, 105877968, 484337300, 2206188412, 10010589904, 45264063504, 204016241794, 916898737038, 4109984712933, 18379240912034, 82012499946246, 365245641944278, 1623757696702586, 7207073607368924, 31941896126213722, 141377838141158888, 624983649220555836, 2759711619634526196, 12173102200970091434

Offset: 0

Author

Paul D. Hanna, Aug 14 2016

Keywords

• sign

Comments

The g.f. of A274965 equals G(x,1), where G(x,y) = x*y + G(x,x*y)^2 is the g.f. of A275670.

First negative term is at a(646).

Examples

			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 +...
		

Links

• Paul D. Hanna, Table of n, a(n) for n = 0..1024

Crossrefs

Cf. A274965, A275752.

Programs

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), ", "))