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A108531
Number of mobiles (cycle rooted trees) with n nodes and 2-colored internal (non-leaf) nodes.
5
1, 2, 6, 18, 60, 206, 770, 2950, 11748, 47746, 197808, 830878, 3532790, 15168294, 65683552, 286504378, 1257693038, 5551978426, 24630911086, 109759215338, 491060888588, 2204938828766, 9933016712348, 44881199711338
OFFSET
1,2
FORMULA
Shifts left and halves under CIK transform.
PROG
(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=1+2*CIK(x*p, i)); Vec(p)} \\ Andrew Howroyd, Jun 20 2018
CROSSREFS
KEYWORD
nonn,eigen
AUTHOR
Christian G. Bower, Jun 07 2005
STATUS
approved