%I #5 Oct 21 2018 16:06:27

%S 1,2,2,2,4,12,32,72,148,318,772,2014,5216,13060,32168,80176,204714,

%T 531054,1380492,3574768,9247262,24023702,62819630,165074070,434726670,

%U 1145890266,3024348486,7999762500,21214170582,56378759128,150069876570

%N Expansion coefficients of the solution of a functional equation.

%F G.f. A(x) satisfies A(x) = x * f(x, A(x)) where f(, ) is Ramanujan's general theta function.

%e G.f. = x + 2*x^2 + 2*x^3 + 2*x^4 + 4*x^5 + 12*x^6 + 32*x^7 + 72*x^8 + ...

%o (PARI) {a(n) = my(A); if( n<1, 0, A = x + O(x^2); for(k=2, n, A = x * sum(i= -sqrtint(n-1), sqrtint(n+2), x^((i^2+i)/2) * A^((i^2-i)/2))); polcoeff(A, n))};

%K nonn

%O 1,2

%A _Michael Somos_, May 26 2005