A032201 Number of rooted compound windmills with n nodes and leaves of 2 colors.

2, 2, 5, 13, 40, 128, 457, 1660, 6308, 24409, 96363, 385535, 1561706, 6387135, 26347199, 109471366, 457758461, 1924845582, 8134171456, 34526723986, 147139513066, 629314845284, 2700401538933, 11622130671430

Offset: 1

Author

Christian G. Bower

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..200
• Index entries for sequences related to mobiles

Programs

PARI

CIK(p,n)={sum(d=1, n, eulerphi(d)/d*log(subst(1/(1+O(x*x^(n\d))-p), x, x^d)))}
seq(n)={my(p=O(1));for(i=1, n, p=2+CIK(x*p, i)); Vec(p)} \\ Andrew Howroyd, Jun 20 2018

Formula

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