A108526 Number of mobiles (cycle rooted trees) with n generators.

1, 2, 5, 16, 54, 210, 841, 3555, 15402, 68336, 308206, 1410175, 6525500, 30492934, 143669529, 681781043, 3255653089, 15632422715, 75429279214, 365556955492, 1778608580060, 8684658137204, 42543288504844, 209022441144144

Offset

1,2

Comments

A generator is a leaf or a node with just one child.

Links

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

C. G. Bower, Transforms (2)

Index entries for sequences related to mobiles

Formula

G.f. satisfies (2-x)*A(x) = x - 1 + CIK(A(x)).

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=x); for(n=2, n, p += x^n*polcoef(x*p + CIK(p, n), n)); Vecrev(p/x)} \\ Andrew Howroyd, Aug 31 2018

Crossrefs

Cf. A108521-A108529, A032200, A032203.

Sequence in context: A149967 A148400 A052836 * A363201 A321470 A149968

Adjacent sequences: A108523 A108524 A108525 * A108527 A108528 A108529

Keyword

nonn

Author

Christian G. Bower, Jun 07 2005

Status

approved