A172402 - OEIS

%I #2 Mar 30 2012 18:37:21

%S 1,1,3,16,166,3464,146167,12437880,2127406440,729774938584,

%T 501412103054958,689540993399039000,1897244652767973627366,

%U 10442429807446111573892528,114961543001288361817819197405

%N G.f.: 1/(1-x) = Sum_{n>=0} a(n)*x^n/(1+x)^(2^(n+1)-2).

%F Column 1 of triangle A172400.

%e 1/(1-x) = 1 + x/(1+x)^2 + 3*x^2/(1+x)^6 + 16*x^3/(1+x)^14 + 166*x^4/(1+x)^30 +...

%o (PARI) {a(n)=if(n==0,1,polcoeff(-(1-x)*sum(m=0,n-1,a(m)*x^m/(1+x +x*O(x^n))^(2^(m+1)-2)),n))}

%Y Cf. A172400, A172401, A172403.

%K nonn

%O 0,3

%A _Paul D. Hanna_, Feb 01 2010