A055351 Number of labeled mobiles (circular rooted trees) with n nodes and 4 leaves.

30, 1500, 47250, 1234800, 29635200, 685843200, 15717240000, 362244960000, 8476532064000, 202580554176000, 4963223577312000, 124948285862400000, 3236755595673600000, 86346680044584960000, 2372991796225290240000

Offset: 5

Author

Christian G. Bower, May 15 2000

Keywords

• nonn

Links

• Georg Fischer, Table of n, a(n) for n = 5..250
• Index entries for sequences related to mobiles

Crossrefs

Column 4 of A055349.

Programs

Mathematica

m = 20; L[x_] = Log[1 - x] + O[x]^m // Normal; A[_] = 0;
Do[A[x_] = x y - x  L[A[x]] + O[x]^k // Normal // Expand, {k, m}];
Drop[(SeriesCoefficient[#, {y, 0, 4}] & /@ CoefficientList[A[x], x]) * Range[0, m - 1]!, 5] (* Jean-François Alcover, Nov 01 2019 *)