OFFSET
0,3
COMMENTS
Limit a(n)/3^[n(n-1)/2] = 1.361839192264541770366149558100...
EXAMPLE
G.f.: A(x) = 1 + x + 3*x^2 + 30*x^3 + 892*x^4 + 76554*x^5 +...
Related functions are defined by:
A(x) = 1 + x*B(x)^3;
B(x) = 1 + x*C(x)^9;
C(x) = 1 + x*D(x)^27;
D(x) = 1 + x*E(x)^81;
E(x) = 1 + x*F(x)^243; ...
where the coefficients in the above functions begin:
B=[1,1,9,279,24870,6324282,4695640434,10341522771762,...];
C=[1,1,27,2538,678708,515666952,1144737153180,7549554318496218,...];
D=[1,1,81,22923,18390510,41861447352,278471836036890,...];
E=[1,1,243,206550,497133612,3393278306694,67693048457727060,...];
F=[1,1,729,1859679,13427919990,274923122390262,16451387497191947778,...].
PROG
(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(j=0, n-1, A=1+x*A^(3^(n-j))); polcoeff(A, n)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jan 17 2011
STATUS
approved