A032172 - OEIS

A032172

Number of rooted compound windmills with n nodes and leaves of 2 colors with no symmetries.

2, 2, 3, 9, 27, 93, 317, 1148, 4203, 15781, 60066, 231968, 905301, 3567982, 14175319, 56722193, 228380002, 924598874, 3761536993, 15370095298, 63051505041, 259573763572, 1072091242996, 4441058718736

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..200

Index entries for sequences related to mobiles

FORMULA

Shifts left under "CHK" (necklace, identity, unlabeled) transform.

PROG

(PARI)

CHK(p, n)={sum(d=1, n, moebius(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+CHK(x*p, i)); Vec(p)} \\ Andrew Howroyd, Jun 20 2018

CROSSREFS

Sequence in context: A275329 A021821 A019234 * A032103 A091044 A079661

Adjacent sequences: A032169 A032170 A032171 * A032173 A032174 A032175

KEYWORD

nonn

AUTHOR

Christian G. Bower

STATUS

approved