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Number of rooted compound windmills with n nodes and leaves of 2 colors.
2

%I #13 Jun 20 2018 16:37:44

%S 2,2,5,13,40,128,457,1660,6308,24409,96363,385535,1561706,6387135,

%T 26347199,109471366,457758461,1924845582,8134171456,34526723986,

%U 147139513066,629314845284,2700401538933,11622130671430

%N Number of rooted compound windmills with n nodes and leaves of 2 colors.

%H Andrew Howroyd, <a href="/A032201/b032201.txt">Table of n, a(n) for n = 1..200</a>

%H <a href="/index/Mo#mobiles">Index entries for sequences related to mobiles</a>

%F Shifts left under "CIK" (necklace, indistinct, unlabeled) transform.

%o (PARI)

%o CIK(p,n)={sum(d=1, n, eulerphi(d)/d*log(subst(1/(1+O(x*x^(n\d))-p), x, x^d)))}

%o seq(n)={my(p=O(1));for(i=1, n, p=2+CIK(x*p, i)); Vec(p)} \\ _Andrew Howroyd_, Jun 20 2018

%K nonn

%O 1,1

%A _Christian G. Bower_